Anti-leukocyte recruitment therapy for the treatment of seizures and epilepsy

ABSTRACT

Methods are provided for the prevention and treatment of seizures and epilepsy. It is shown herein that leukocyte recruitment plays a key role in the pathogenesis of epilepsy. Treatment with an agent that inhibits leukocyte recruitment has therapeutic and preventative effects in blocking recurrent seizures and epilepsy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This applications claims benefit of priority to US provisionalapplication 60/811,873, filed Jun. 7, 2006, which is herein incorporatedby reference.

This invention was made with Government support under contract A147822and GM37734. The government has certain rights in this invention.

BACKGROUND OF THE INVENTION

A seizure is a paroxysmal event due to abnormal, excessive,hypersynchronous discharges from an aggregate of central nervous system(CNS) neurons, while epilepsy is a condition in which a person hasrecurrent seizures due to a chronic, underlying process. Experimentaland clinical data indicate that the occurrence of repeated seizures canlead to an epileptic condition. It is therefore of great interest toidentify possible pharmacological treatments for seizures, and thetime-frame in which such treatment is effective.

Epilepsy is a brain disorder characterized by, periodic andunpredictable seizures caused by the rhythmic firing of large groups ofneurons. The behavioral manifestations of epileptic seizures in humanpatients range from mild twitching of an extremity to loss ofconsciousness and uncontrollable convulsions. Up to 1% of the populationis afflicted, making epilepsy one of the most common neurologicalproblems. The abnormal activity associated with epilepsy generatesplastic changes in cortical circuitry that play a part in thepathogenesis of the disease. The importance of synaptic plasticity inepilepsy is indicated most clearly by an animal model of seizureproduction called “kindling.” Over a period of time, a weak stimulusthat initially had no effect will eventually cause full-blown seizures.This phenomenon is essentially permanent; even after an interval of ayear; the same weak stimulus will again trigger a seizure.

Research has focused on where seizures originate and the mechanisms thatmake the affected region hyperexcitable. Evidence suggests that abnormalactivity in cerebral cortex foci provide the triggers for a seizure thatthen spreads to other synaptically connected regions. Epileptic seizurescan be caused by a variety of acute or congenital factors, includingcortical damage from trauma, stroke, tumors, congenital corticaldysgenesis, and congenital vascular malformations.

No effective prevention or cure exists for epilepsy. Pharmacologicaltherapies that successfully inhibit seizures are based on two generalstrategies. One approach is to enhance the function of inhibitoryGABAergic synapses; the other is to limit action potential firing byacting on voltage-gated Na⁺ channels. Commonly used antiseizuremedications include carbamazepine, phenobarbital, phenytoin, andvalproic acid. These agents must be taken daily, and only inhibitseizures in 60-70% of patients.

A number of processes are thought to contribute to the development ofepilepsy including enduring increases in excitatory synaptictransmission, changes in GABAergic inhibition, neuronal cell death andthe development of aberrant innervation patterns in part arising fromreactive axonal growth. It has also been suggested that activities ofintegrin class adhesion receptors play roles in each of these processesby stabilizing activity-induced increases in synaptic strength andexcitability. These same adhesion proteins and proteases play criticalroles in axonal growth and synaptogenesis including processes induced byseizure in adult brain (Gall et al. (2004) Adv Exp Med Biol. 548:12-33).

REFERENCES

Holmes (2002) Seizure-induced neuronal injury: animal data. Neurology59, S3-S6; Holmes et al. (2002) Seizure-induced damage in the developinghuman: relevance of experimental models. Prog. Brain Res. 135, 321-334;Duncan (2002) Seizure-induced neuronal injury: human data. Neurology 59,S15-S20; Duncan (2002) MRI studies. Do seizures damage the brain? Prog.Brain Res. 135, 253-261.

Parfenova et al. (2005) Epileptic seizures cause extended postictalcerebral vascular dysfunction that is prevented by HO-1 overexpression.Am J Physiol Heart Circ Physiol 288, H2843-H2850; Yabuuchi et al. (1993)In situ hybridization study of interleukin-1 beta mRNA induced by kainicacid in the rat brain. Brain Res. Mol. Brain Res. 20, 153-161;Plata-Salaman et al. (2000) Kindling modulates the IL-1beta system,TNF-alpha, TGF-beta1, and neuropeptide mRNAs in specific brain regions.Brain Res. Mol. Brain Res. 75, 248-258; Vezzani et al. (2004) Functionalrole of proinflammatory and anti-inflammatory cytokines in seizures.Adv. Exp. Med. Biol. 548,123-133 (2004).

SUMMARY OF THE INVENTION

Methods are provided for the prevention and treatment of seizures andepilepsy. It is shown herein that leukocyte recruitment plays a key rolein the pathogenesis of epilepsy. Treatment with an agent that inhibitsleukocyte recruitment has therapeutic and preventative effects inblocking recurrent seizures and epilepsy. It is shown herein thatinhibition of leukocyte recruitment through a variety of adhesionmolecules interferes with the pathogenesis of epilepsy, where theexemplary adhesion molecules include VLA-4; VCAM-1, LFA-1, ICAM-1 andPSGL-1.

In some embodiments of the invention the therapeutic agent blocks theinteraction between leukocytes and adhesion molecules present onendothelial cells. Such agents include, without limitation, agents thatblock adhesion molecules involved in leukocyte trafficking and presenton leukocytes or endothelial cells, for example integrins, selectins,mucins, which may be, without limitation, ICAM-1, VCAM-1, beta-2integrins, VLA-4, P-selectin, L-selectin, E-selectin, PSGL-1, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-I. Leukocyte infiltration in human epileptic brains.Representative brain sections of a patient with non-inflammatoryneurological diseases (NIND) (A-C) and of a patient with epilepsy (D-F;see also Table 1). CD45 staining (A,C) revealed leukocytes in brainparenchyma (black arrow), perivascularly (grey arrow) and inside bloodvessels (white arrow) (D). Myeloperoxidase staining (B, E) revealed PMNsin brain parenchyma only in the epileptics (E). CD3-positive cells (C,F) were detected only in epilepsy-suffering group of patients (F). Allthese sections were counter-stained with Nissl staining to outline aprecise anatomical evaluation of leukocyte distribution. (G-I)Morphometric analysis was performed to quantify the number ofcells±SD/mm² (5 slides containing 2 brain sections for each humansubject were analyzed). We analyzed five regions for each brain section(ROIs; number of cells per 41.4 mm²); regions were selected randomly buthad to contain at least one blood vessel. Cells were divided in “insidevessels” and “inside the brain parenchyma”. One way-ANOVA statisticalevaluation was performed, followed by Bonferroni post-hoc test(***P<0.001; **P<0.01). Scale bar is corresponding to 25 μm.

FIG. 2A-H. Induction of vascular adhesion molecules and recruitment ofgranulocytes and activated lymphocytes into the brain after experimentalseizures. (A) Expression of adhesion molecules in cerebral vessels wasdetermined 6 h after the onset of SE. Mice received 50 μg ofAlexa488-labeled mAb intravenously. An isotype-matched antibody was usedas control. Control brains reveal low ICAM-1 expression but absence ofdetectable VCAM-1, E-selectin and P-selectin. Brains in which seizureactivity was suppressed by administration of 3 mg/Kg Diazepam i.p. 20min before pilocarpine injection showed an almost undetectable VCAM-1expression (Diazepam). (B-D) Leukocytes were marked by Resovist®(Schering AG, Germany). This contrast agent consists ofsuperparamagnetic iron oxide (USPIO) nanoparticles coated withcarboxydextran. PMNs and Th1 lymphocytes were injected iv intorecipients either 2 h (for PMNs) or 24 h (for Th1 cells) afterpilocarpine injection. Hypointense MRI spots document intraparenchymalgranulocytes (B) and Th1 cells (C) in the brain after SE (24 h aftercell transfer). Immuno-histochemical staining with Prussian Blueconfirmed the presence of PMNs (D, enlarged in the bottom rectangle) andTh1 cells.

Confocal microscopy shows exogenous (F) and endogenous (E) migratedGr1-positive cells. Fluorescence-labeled PMNs (exogenous cells) wereinjected 2 h post SE and in vivo homing of exogenously administeredlasted 24 h. CD3-positive cells were detected both inside blood vessels(G) and perivascularly (H). Scale bars: (A) 100 μm; (D) 25 μm; bottomrectangle in (D): 8 μm; (E-H) 25 μm.

FIG. 3A-G. Alpha4 integrins mediates leukocyte recruitment afterseizures. A, B. The behavior of PMNs and lymphocyte subpopulations wasstudied at 6 h and 24 h post-SE Cells were CMFDA-labeled orCMTMR-labeled. The number of venules and animals per group is providedat Table 3 and 4. Mean±SEM are shown. PLNs, peripheral lymph node cells.C. Adherent PMNs at 6 h post-SE and Th1 cells at 24 h post SE are shownin cerebral vessels (arrows). Scale bar: 100 μm. D-G. Cells werepretreated with 100 μg/ml PS/2 mAb for 15 min at 25° C. Control cellsreceived no treatment, and were differentially labeled to allow analysisof control and antibody-treated cell in the same venule. The behaviorof >150 cells in 3 venules were analyzed. In other experiments untreatedcells were injected and their behavior analyzed, and then 100 μganti-VCAM-1 or anti-MAdCAM-1 mAbs were injected to assess the effects ofvascular adhesion molecule blockade on behavior. 5 venules were analyzedfor each treatment 6 h post-SE. Hemodynamic parameters were notaffected. Bars depict rolling and arrest fractions (mean±SEM) aspercentage of control cells (untreated for anti-α4 comparison; behaviorprior to antibody injection for anti-VCAM or MAdCAM) that rolled andarrested in the same venule. Groups were compared with control usingKruskall-Wallis test followed by Bonferoni correction of P. **P<0.01;*P<0.001.

FIG. 4A.B. Frequency distribution of Vroll at 6 h and 24 h post-SE. A.B. Frequency distributions of Vroll were calculated after cells wereassigned to velocity classes from >0 μm/s to 5 μm/s; 5 to 10 μm/s; 10 to20 μm/s; and so on. Neutrophils displayed a similar median rollingvelocity (Vroll) at 6 h and 24 h after SE, suggesting that similarmechanisms might account for rolling interactions at the two time points(A, B). (see also Tables 3 and 4). The median Vroll for Th1 lymphocyteswas 18 μm/s at 6 h versus 46 μm/s at 24 h post-SE (Tables 3 and 4),while the distribution in velocity classes showed a larger number ofcells with higher Vroll at 6 h. The transition differences in rollingvelocity in conjunction with the doubling of the rolling fraction isconsistent with the expression of additional vascular adhesionmechanisms in the acute and subacute phases of seizure-inducedinflammation.

FIG. 5A-E. Blockade of alpha4 integrin inhibits seizures and epilepsy.(A-D) 12 animals/group were monitored for 6 h/day for 30 consecutivedays post SE. One representative experiment from a series of 4 withsimilar results is shown. (A) Daily frequency of convulsions per groupwas monitored post SE. Epileptic group received treatment with vehicle(PBS). (B) Change in weight (Δweight from the baseline at day 0, priorto SE induction) is shown. (C, D) The average number of convulsions/dayand the total number of convulsions were calculated for each group.(***P<0.001; *P<0.0001). To study the therapeutic effect, mice weretreated with 200 μg anti-α4 integrin mAb i.p. 1 h after SE onset andthen received 200 μg anti-α4 mAb every other day for 20 days. To studythe preventive effect, mice were treated with 200 μg anti-α4 integrinmAb i.p. 2 h before injection of pilocarpine and then received 200 μganti-α4 mAb every other day for 20 days. (E) Cognitive evaluation basedon enriched open field exploration (in red the animal tracks during the10 minutes test) is shown in 3 representative animals per group.

FIG. 6A-E. Telemetry EEG analysis of anti-α4 integrin treated mice. EEGand movements for each animal were acquired 24 h/day for 20 consecutivedays. Given the continuum of data (24 h/day) we have evaluated theeffect of the treatment as average per total period of recording.Cluster of ictal spikes >3sec were considered as seizures. The minimalinterictal interval between 2 different clusters of spikes was 3 sec.Representative EEG tracks starting 1 h after SE are shown for theepileptic group (A) treated with vehicle, anti-α4-pretreated (B) andtherapeutic treatment starting 1 h after SE (C). Tracks from baseline,SE and chronic phase are provided. The average number of seizures (D)and seizure duration (E) were calculated in 3 animals/group (One-wayANOVA ***, P<0.0001).

FIG. 7A-C. Control mAb has no effect on the induction of seizures andepilepsy. 10 animals/group were monitored for 6 h/day for 30 consecutivedays post SE. The average number of convulsions/day and the total numberof convulsions were calculated for each group. Mice were treated with200 μg anti-CD45 mAb (30G12) i.p. 2 h before injection of pilocarpineand then received 200 μg mAb every other day for 20 days (A and B). (C)Cognitive evaluation based on enriched open field exploration (in redthe animal tracks during the 10 minutes test) is shown in 3representative animals per group.

FIG. 8. LFA-1/ICAM-1 and PSGL-1/P-selectin inhibition blocks adhesiveinteractions in inflamed brain venules after seizures. The behavior ofPMNs was studied at 6 h post-SE. Cells were CMFDA-labeled orCMTMR-labeled. Between 4-6 venules/experimental condition were analyzed.Mean±SEM are shown. Cells were pretreated with 100 μg/ml blocking mAbfor 15 min at 25° C. Control cells received no treatment, and weredifferentially labeled to allow analysis of control and antibody-treatedcell in the same venule. The behavior of >150 cells/venule wereanalyzed. In other experiments untreated cells were injected and theirbehavior analyzed, and then 100 μg anti-ICAM-1, anti-MAdCAM-1 oranti-P-selectin mAbs were injected to assess the effects of vascularadhesion molecule blockade on behavior. Hemodynamic parameters were notaffected. Bars depict rolling and arrest fractions (mean±SEM) aspercentage of control cells (untreated for anti-LFA-1/PSGL-1 comparison;behavior prior to antibody injection for anti-ICAM, anti-MAdCAM-1 orP-selectin) that rolled and arrested in the same venule. Groups werecompared with control using Kruskall-Wallis test followed by Bonferonicorrection of P. *P<0.01; §P<0.001.

FIG. 9A-C. Effect of anti-LFA-1 and anti-ICAM-1 therapy onpilocarpine-induced epilepsy. 10 animals/group were monitored for 6h/day for 30 consecutive days post SE. One representative experimentfrom a series of 2 with similar results is shown. (A, B) Daily frequencyof convulsions per group was monitored post SE. Epileptic group receivedtreatment with vehicle (PBS). The average number of convulsions/day andthe total number of convulsions were calculated for each group. To studythe therapeutic effect, mice were treated with 200 μg anti-αL integrinor anti-ICAM-1 mAb i.p. 30 min after SE onset and then received 200 μgmAb every other day for 20 days. To study the preventive effect, micewere treated with 200 μg anti-αL integrin or anti-ICAM-1 mAb i.p. 2 hbefore injection of pilocarpine and then received 200 μg mAb every otherday for 20 days. *P<0.0001. (C) Cognitive evaluation based on enrichedopen field exploration (in red the animal tracks during the 10 minutestest) is shown in 3 representative animals per group.

FIG. 10A-C. Effect of PSGL-1 and FucTs deficiency on the induction ofepilepsy. 10 animals/group (A and B) were monitored for 6 h/day for 30consecutive days post SE. One representative experiment from a series of3 with similar results is shown. The average number of convulsions/dayand the total number of convulsions were calculated for each group.(***P<0.001; *P<0.0001). (C) Cognitive evaluation based on enriched openfield exploration (in red the animal tracks during the 10 minutes test)is shown in 3 representative animals per group.

FIG. 11. Telemetry EEG analysis of PSGL-1 and FucT-VII deficient mice.EEG and movements for each animal were acquired 24 h/day for 20consecutive days. Given the continuum of data (24 h/day) we haveevaluated the effect of the treatment as average per total period ofrecording. Cluster of ictal spikes ≧3sec were considered as seizures.The minimal interictal interval between 2 different clusters of spikeswas 3 sec. The average number of seizures and seizure duration werecalculated in 3 animals/group (One-way ANOVA *, P<0.0001; ***P<0.001).

FIG. 12. Evaluation of vascular alterations post-SE in wt and PSGL-1 andFucTs deficient mice. The blood-brain barrier permeability was studiedby the mean of intravenously administered Magnevist® (Nmethylglucaminesalt of gadolinium complex of diethylenetriamine pentaacetic acid) aparamagnetic iron oxide contrast agent in MRI. Pre-contrast image of ananimal after SE, Post-contrast image of the same mouse and pseudo-colormap evidencing contrast agent spreading in the cortical areas (arrows)nearby the middle cerebral artery are provided. Extravasated blood fromparenchyma is drained by choroid plexus in the cerebral ventricles,which become hyperintense in MRI.

FIG. 13. Increased vascular diameter after Status epilepticus. Bloodvessels diameter was measured before and after pilocarpineadministration (6 h) as described for intravital microscopy experiments.

FIG. 14. Effect of pilocarpine on leukocyte adhesion. Total leukocyteswere isolated from the blood of normal mice by using hypotonic lysis oferythrocytes. Adhesion assays were performed on eighteen well glassslides coated with VCAM-1. Cells were treated with pilocarpine atdifferent concentrations and time points as indicated. After 20 min,slides were washed, fixed and computer-assisted enumeration of boundcells was performed. The results are presented as percentage of control(untreated) cells and show no effect of pilocarpine on leukocyteadhesion.

FIG. 15. Induction of adhesion molecules in brain vessels after seizuresinduced with Kainic acid. Expression of adhesion molecules in cerebralvessels was determined 24 h after the onset of SE in mice receiving i.p.30 mg/kg Kainic acid (Cayman Chemicals, Mich., USA). Mice received 50 μgof Alexa488-labeled mAb intravenously. An isotype-matched antibody wasused as control. In vivo staining revealed expression of P-selectin andICAM-1 and high level expression of VCAM-1 on both venules andarterioles. Control brains reveal low ICAM-1 expression but absence ofdetectable VCAM-1, E-selectin and P-selectin.

DETAILED DESCRIPTION OF THE INVENTION

Methods are provided for protecting or treating an individual sufferingfrom adverse effects of repeated seizures. Administration of agents thatinhibit leukocyte recruitment in the central nervous system are usefulin the treatment of seizures, including the prevention of recurrentseizures, and the development of epilepsy.

Therapeutic agents for use in the methods of the invention blockadhesion molecules present on endothelial cells or those that arepresent on leukocytes, including, without limitation, integrin specificantibodies and derivatives thereof, including antibodies and derivativesthereof having specificity for integrins, selectins or mucins; andsoluble counter-receptors of selecting, integrins or mucins, e.g. PSGL-1and fusion proteins derived therefrom, MAC-1 and fusion proteins derivedtherefrom; and the like. Such fusion proteins may be a fusion betweenimmunoglobulin constant region domains and the soluble form of thecounterreceptor.

Repeated seizures can lead by unknown mechanisms to chronic epilepsy,requiring life long anti-convulsant therapy. It is shown herein thatleukocyte recruitment plays a key role in the pathogenesis of epilepsy.Repeated seizures induce increased permeability, vasodilatation andexpression of VCAM-1 on central nervous system vessels, and migration ofleukocytes into the brain. Leukocytes, including granulocytes and Tcells, then accumulate in the brains of patients with epilepsy.

Therapeutic treatment with an agent that inhibits leukocyte recruitmentinhibits leukocyte interactions with brain vessels, and leads to adrastic reduction in seizure activity. Strikingly, preventiveadministration blocks recurrent seizures and development of epilepsy.The results provided herein demonstrate an unexpected role for leukocyterecruitment in the pathogenesis of epilepsy, and show thatanti-leukocyte adhesion therapy has therapeutic and preventative effectsin epilepsy. Molecules demonstrated to have a role in the pathogenesisof epilepsy include VLA-4, VCAM-1, LFA-1, ICAM-1 and PSGL-1.

Leukocyte recruitment into tissues through the vascular endotheliumtypically involves a complex interaction between endothelial cells (EC)present in vessel walls, e.g. high endothelial venules; activatingagents, such as cytokines and chemokines; and leukocyte recruitment andmigration. A progressive sequence of binding events among cognate pairsof EC CAMs and leukocyte ligands serves as a prelude to leukocytetransmigration across endothelium. These steps are usually described astethering, rolling, leukocyte activation, and firm adhesion. Generallyrecruitment involves interaction between proteins present on endothelialcells, e.g. selectins, ICAM, VCAM, etc., and proteins present onleukocytes, e.g. integrins, L-selectin, mucin PSGL-1, etc. Humanizedanti-adhesion molecule antibodies; and soluble counterreceptors andfusion products derived therefrom are publicly available and theirtoxicity, beneficial and undesired effects have been studied in severalhuman inflammatory diseases.

Recruitment may also involve chemokines and chemokine receptors. In someembodiments of the invention blockade of chemokine signaling involved inleukocyte trafficking to the central nervous system is used as atherapeutic option.

Adhesion Molecules

In some embodiments of the invention, the therapeutic agent is anintegrin antagonist, for example an antagonist, including monoclonalantibodies having specificity for an integrin, e.g. a β2 integrin, a β1integrin, a β7 integrin, an αI, αM, αX, αD, α4, α9, αv, etc. In oneembodiment of the invention, the agent is an antagonist of α4 integrin,an antagonist of CD11b, an antagonist of CD11a, or an antagonist ofCD18.

The integrin family includes a number of molecules involved in leukocytetrafficking and recruitment. On leukocytes, the β2-integrin subunit(CD18) forms various heterodimers with α-integrin subunits, e.g. αLβ2(LFA-1), αMβ2, αXβB2, αDβ2, enabling their interactions with counterreceptors of the IgG-domain family on the surface of activatedendothelial cells or multiple ligands of the extracellular matrix. Thesediverse interactions allow firm adhesion of chemokine-stimulatedleukocytes to endothelial cells, followed by diapedesis and chemotaxisthrough damaged or infected tissues. Reagents include antibodies orantibody fragments, e.g. see U.S. Pat. Nos. 6,689,869; 5.997,687, hereinincorporated by reference.

The αMβ2 integrin is of particular interest. It is expressed inmonocytes, granulocytes, macrophages and natural killer cells and hasbeen implicated in diverse responses of these cells, includingphagocytosis, cell-mediated killing and chemotaxis. These complexresponses depend on the capacity of αMβ2 integrin to mediate leukocyteadhesion and migration, playing a central role in inflammation. αMβ2 andalso αXβ2 integrins recognize a large set of structurally unrelatedligands, including fibrinogen, complement fragment iC3b, ICAM-1, FactorX, JAM's and denatured proteins. Reagents specific for αMβ2 includehumanized antibodies and antibody fragments specific for alphaM (CD11b)and for beta2 as described above.

Also of particular interest is αLβ2 integrin (LFA-1). For example theantibody RAPTIVA binds to the αL subunit (CD11a). RAPTIVA inhibits thebinding of LFA-1 to intercellular adhesion molecule-1 (ICAM-1), therebyinhibiting the adhesion of leukocytes to other cell types. Interactionbetween LFA-1 and ICAM-1 contributes to the initiation and maintenanceof multiple processes, including activation of T lymphocytes, adhesionof T lymphocytes to endothelial cells, and migration of T lymphocytes tosites of inflammation including psoriatic skin.

αDβ2 integrin is expressed on eosinophils, monocyte/macrophages andneutrophils and is an alternative receptor for VCAM-1.

α4β1 and α9β1 are dual specific integrins that recognize fibronectin atsites distinct from the major RGD containing cell binding site, andVCAM-1 exposed on endothelial cells. The α4β1 and α9β1 integrins appearto specifically enhance cell migration. During inflammation, leukocytemigration across the endothelium is facilitated by the interaction ofα4β1 with VCAM-1. Integrin α4β1 induced cell migration depends on theinteraction of the α4 cytoplasmic tail with the focal adhesion adaptorprotein paxillin. α9β1 integrin also interacts with paxillin, but itlacks the regulatory phosphorylation site and enhances cell motilityindependent of paxillin binding. αvβ1 integrin has specificity for RGDcontaining extracellular ligands.

The αv subunit can bind several different β-integrin subunits (αvβ1,αvβ3, αvβ5, αvβ6, αvβ8) forming heterodimers with specificities for RGDpeptide containing ligands. Among these different heterodimers, αvβ3integrin is the most studied in association with cell migration.

The β7-integrin subunit, like β2-integrin, is expressed exclusively incells of the hematopoietic system. The β7-integrin subunit pairs withthe α4 and αE integrin chains forming α4β7 and αEβ7 integrins. α4β7 isinvolved in the morphogenesis of the gut-associated lymphatic system,while αEβ7 regulates immuno-surveillance of the skin. The β7-integrinsare also involved in CD8⁺ T-cell mediated graft rejection.

One of the endothelial molecules involved in lymphocyte trafficking isvascular adhesion protein-1 (VAP-1). VAP-1 is a cell-surface enzymebelonging to a specific group of amine oxidases (semicarbazide-sensitiveamine oxidases [SSAOs] Enzyme Commission 1.4.3.6) that catalyzeoxidative deamination of primary amines (see, for example, Salmi et al.(1992) Science 257:1407-1409; Koskinen et al. (2004) Blood103:3388-3395). VAP-1 mediates PMN-endothelial cell interactions invitro and in vivo. The adhesive function of VAP-1 is dependent on itsenzymatic activity during the rolling and transmigration steps of theextravasation cascade under physiologically relevant shear conditions.Blocking the SSAO activity by enzyme inhibitors, e.g. by BTT-2027,effectively ameliorates the development of an inflammatory reaction invivo, alternatively it has been shown that an anti-VAP-1 mAb blocksextravasation of PMNs.

The selectins and the immunoglobulin (Ig) superfamily are 2 differentfamilies of apical surface EC adhesion molecules responsible forleukocyte recruitment from blood. Selectins are adhesion moleculesinvolved in tethering and rolling of lymphocytes during the migrationinto lymphoid or non-lymphoid organs. Three selectins have beenidentified: L-, P- and E-selectin. All three selectins are type Itransmembrane glycoproteins that bind sialylated carbohydrate structuresin a Ca2+-dependent manner. Each selectin has a lectin-like domain andvarious numbers of consensus repeat domains which show homology tocomplement regulatory proteins. The lectin domains of the threeselectins share about 60% homology, which results in subtle differencesin carbohydrate binding and confers selectin specificity.

L-selectin (CD62L) is expressed on the microvillae of naïve lymphocytesand central memory T cells and is important for lymphocyte homing andadhesion to high endothelial cells of post capillary venules ofperipheral lymph nodes and Peyer's patches. L-selectin is critical tothe capture/tethering during the migration through the endotheliallining. It interacts with endothelial mucin MAdCAM-1 in Peyer's patches.In addition, L-selectin binds to endothelial ligands, most of which arecharacterized by MECA-79 reactivity and are collectively known asperipheral node addressins (PNADs). The glycoprotein structure(s) thatexpress the MECA-79 antigen are not completely known, but include CD34.It has been also reported that L-selectin might interact with mucinPSGL-1 (P-selectin glycoprotein ligand-1) expressed by adheredleukocytes and this may help to deliver L-selectin bearing lymphocytesin sites of inflammation.

P-selectin (CD62P) is costitutively expressed on the endothelium of lungand choroids plexus microvessels and on the platelet surface afteractivation, while E-selectin is costitutively expressed in normal skinvessels. Both E- and P-selectin are upregulated by inflamed endotheliumin most organs during inflammatory diseases. PSGL-1 is considered themain lymphocyte ligand for P-selectin and is also able to bind E- andL-selectin. Although PSGL-1 mucin is expressed by all T cells, it is notalways glycosylated properly for selectin binding and this explains whynaïve T cells cannot bind P- and E-selectins.

All selectin ligands are carbohydrate-containing molecules, and severalglycosyltransferases have a role in the biosynthesis of selectinligands. These include two α1,3-fucosyltransferases, FucT-IV andFucT-VII, the O-linked branching enzyme core 2β1,6-glucosaminyltransferase-I(C2GIcNAcT-I), aβ1,4-galactosyltransferase-I(b1,4GalT-I), and at least twosialyltransferases of the ST3Gal family that add sialic acid togalactose in a 2-3 linkage. In addition, at least one of two tyrosinesulphotransferases must be active to produce high-affinity P-selectinbinding, and the sulphated tyrosine residues of PSGL-1 directlyparticipate in P-selectin binding.

P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric, mucin-typeglycoprotein ligand originally identified as a ligand for P-selectin.PSGL-1 is expressed on the surface of all lymphocytes and is a ligandfor E- P- and L-selectin. Much attention has been given to theN-terminal region of PSGL-1 as it contains binding regions for theselectins. P-selectin binds to the extreme N terminus of PSGL-1 byinteracting stereo specifically with clustered tyrosine sulfates and anearby core 2O-glycan with a sialyl Lewis x (sLex) epitope (C2-O-sLex).Similarly, L-selectin binds with high affinity to the N-terminal regionof PSGL-1 through cooperative interactions with three sulfated tyrosineresidues and an appropriately positioned C2-O-sLex O-glycan.E-selectin-PSGL-1 binding seems to be sulfation-independent requiringsLex and glycosylation of PSGL-1 by alpha (1,3) fucosyltransferases.Expression of Cutaneous lymphocyte antigen (CLA,) afucosyltransferaseVII-dependent carbohydrate modification of PSGL-1, isclosely correlated with interactions between PSGL-1 and E-selectin. Ithas been previously demonstrated that FucT-VII expression is high in Th1cells, while Th2 lymphocytes expresses high levels of FucT-IV, but notFucT-VII. Moreover, Th1 cells, but not Th2 cells, are able to bind toP-selectin and E-selectin. It has been shown that targeted deletions ofthe FucT-IV and FucT-VII loci yield a severe attenuation of lymphocytemigration to secondary lymphoid organs and to sites of cutaneousinflammation. Moreover, it has been recently shown that efficientrecruitment of activated lymphocytes to the brain in the contextsmimicking EAE is controlled by FucT-VII and its cognate cell surfaceantigen CLA expressed by PSGL-1.

PSGL-1-mediated tethering and rolling in vivo depends on theinteractions with E and P-selectin expressed by endothelium or byP-selectin presented by adhered platelets on the vessel wall. Moreover,it has been shown that also the interactions between the leukocyteadhesion receptor L-selectin and PSGL-1 play an important role in vivoin regulating the inflammatory response by mediating leukocyte tetheringand rolling on adherent leukocytes.

An agent of interest is YSPSL, also referred to as (rPSGL-Ig). YSPSL isa recombinant molecule resulting from fusion of P-selectin glycoproteinligand (PSGL-1) and human IgG1, and is described, inter alia, by Opal etal. (2001) Shock 15:285,290; and Scalia et al. (1999) Circ. Res.84:93-102, each herein incorporated by reference.

ICAM-1 (CD54) is a type I integral membrane glycoprotein with repeatingIg domains in the extracellular region, a structural signature of the Igsuperfamily. Heterogeneity among different cell types gives rise toM_(r) for ICAM-1 of 97 to 114 kd, most likely resulting fromdifferential patterns of glycosylation. The non-N-glycosylated form hasan M_(r) of 55,000. A second ICAM isoform, ICAM-2 (CD102; M_(r) 55-65kd), is partially homologous to ICAM-1 but has only 2 Ig-likeextracellular domains compared with 5 such domains for ICAM-1. ICAM-1 isbelieved important for leukocyte recruitment during a wide range ofinflammatory and noninflammatory circumstances.

VCAM (CD106, M_(r) 100-110 kd) is expressed by activated ECs andfollicular dendritic cells. The VCAM extracellular domain containsrepeating Ig domains, but because of alternate posttranscriptionalsplicing there are 2 VCAM messenger RNAs, a more abundant full lengthtranscript and a variant that lacks exon 5. The VCAM variant maintainsthe same cytoplasmic domain but has a shorter extracellular domain. Aswith E-selectin, the cytoplasmic tail of human VCAM shows substantialhomology across species.

ICAM-1, ICAM -2, and VCAM each promote firm adhesion to ECs. Moreover,VCAM and to a greater extent ICAM-1 probably assist leukocyte entry intothe interendothelial junction. These Ig-CAMs interact with differentintegrin heterodimers expressed on the leukocyte surface: ICAM-1 andICAM-2 interact with leukocyte function-associated antigen-1 (LFA-1)expressed on all leukocytes, ICAM-1 (but not ICAM-2) interacts withmacrophage receptor-1 (Mac-1) expressed on neutrophils, and VCAMinteracts with very late antigen-4 (VLA-4) on lymphocytes, monocytes,and eosinophils, but only rarely expressed on neutrophils.

The ability of T cells to leave the circulation depends on theiractivation state. Activation occurs during rolling, when leukocytesencounter chemoattractants, e.g. C5a, platelet activating factor,leukotriene B₄, formyl peptides, and chemoattractant cytokines, e.g.chemokines. Chemokines bind to specific leukocyte receptors that triggerheterotrimeric G-protein-dependent leukocyte signaling. Such signalslead to clustering, and greater affinity/avidity of the integrins LFA-1,Mac-1, and VLA-4 for their cognate Ig-superfamily EC-CAMs. Otherintracellular events signaling activation are induced in leukocytesduring E-selectin tethering, VLA-4 cross-linking, or LFA-1 binding toICAM-1. In some embodiments, recruitment of leukocytes is blocked by theadministration of agents that inhibit the activity of chemokines orchemokine receptors.

The class of IgCAMS is of interest. These molecules can be involved inthe adhesion of leukocytes, e.g. via LFA/ICAM-1, VLA4NCAM-1, etc. Themolecules include the following:

SYSTEMIC IgCAMS Molecule Ligands Distribution ALCAM (CD166) CD6; CD166;Neural; Leukocytes NgCAM; 35 kD protein Basigin (CD147) Leukocytes;RBCs; Platelets; Endothelial cells BL-CAM (CD22) SialylatedB-Lymphocytes glycoproteins LCA (CD45) CD44 Hyaluronin; Ankyrin;Lymphocytes; Epithelial; Fibronectin; MIP1β WM perivascular Osteopontinastrocytes ICAM-1 (CD54) αLβ2; LFA-1 Leukocytes; Endothelial cells;Dendritic cells; Fibroblasts; Epithelium; Synovial cells ICAM-2 (CD102)αLβ2 (LFA-1) Endothelial cells; Lymphocytes; Monocytes ICAM-3 (CD50)αLβ2 Leukocytes Lymphocyte LFA-3 Lymphocytes; Thymocytes functionantigen-2 (LFA-2) (CD2) LFA-3 (CD 58) LFA-2 Leukocytes; StromaEndothelial cells Astrocytoma MAdCAM-1 α4β7; Mucosal endothelialL-selectin cells PECAM (CD31) CD31; αvβ3 Leukocytes; Synovial cellsEndothelial cells VCAM-1 α4β1; α4β7 Satellite cells Monocytes; Synovialcells; Activated endothelial cells

In addition to adhesion molecules, leukocyte migration and/ortrafficking may be inhibited with agents that act to inhibit chemokinesor chemokine receptors. Chemokine/chemokine receptor pairs relevant toleukocyte migration and trafficking include, for example,CCL2(MCP-1)/CCR2; CCL3 (MIP1alpha)/CCR1, CCR5; CCL4(MIP-1beta)/CCR5;CCL5 (RANTES)/CCR5; CCL17 (TARC)/CCR4; CCL22 (MDC)/CCR4; CCL19(MIP-3beta)/CCR7; CCL21 (SLC)/CCR7; CXCL1(Gro-alpha)/CXCR2; CXCL8(IL8)/CXCR1, CXCR2; CXCL9 (MIG)/CXCR3; CXCL10 (IP-10)/CXCR3; and CXCL12(SDF-1)/CXCR4; and CCR1 and its ligands. In addition to chemokines,agents that inhibit other chemoattractants or chemoattractant receptorscan inhibit leukocyte migration and/or trafficking. Chemoattractant/receptor pairs relevant to leukocyte migration and trafficking includeLTB4/BLT1, complement component C5a/C5aR, and chemerin/CMKLR1. Agents,e.g. small molecule antagonists, monoclonal antibodies, etc. thatinterfere with the interaction between a chemokine or otherchemoattractant with its cognate receptor are useful in the methods ofthe invention.

Alternatively, blocking integrin-outside in signaling may be used toinhibit leukocyte trafficking to the central nervous system. Blockade ofsignal transduction pathways generated after integrin engagement(outside-in signaling) inhibits adhesion stabilization and migration ofleukocytes in sites of inflammation. As for instance blockade ofinteractions between the cytoplasmic tail of alpha4 integrins andpaxillin. Paxillin, a signaling adaptor molecule, binds directly to thealpha4 cytoplasmic tail and its binding is important for cell migration.Interfering with alpha4 signaling by inhibiting the alpha4-paxillininteraction decreases alpha4-mediated cell migration and adhesion toVCAM-1 and MadCAM under shear flow. These in vitro effects areaccompanied by a selective impairment of leukocyte migration intoinflammatory sites when the alpha4-paxillin interaction is blocked invivo. Similarly, it has been shown that perturbance of outside-insignaling by beta2 integrins impairs the inflammatory responses inanimal models (Lowel and Berton, PNAS, 1998; Vicentini et al., J.Immunol., 2002; Evangelista et al., Blood 2007, each specificallyincorporated by reference). Thus, drugs that block alpha4beta1-integrinor alphaLbeta2 and alphaMbeta2 integrin outside-in signaling can havetherapeutic effects for seizures and epilepsy. These in vitro effectsare accompanied by a selective impairment of leukocyte migration intoinflammatory sites when the alpha4-paxillin interaction is blocked invivo (Feral etal., 2006J. Clin. Invest 116, 715-723).

Adhesion Molecule Antagonists

As used herein, an “antagonist,” refers to a molecule which, wheninteracting with (e.g., binding to) a target protein, decreases theamount or the duration of the effect of the biological activity of thetarget protein (e.g., interaction between leukocyte and endothelial cellin recruitment and trafficking). Antagonists may include proteins,nucleic acids, carbohydrates, antibodies, or any other molecules thatdecrease the effect of a protein. Unless otherwise specified, the term“antagonist” can be used interchangeably with “inhibitor” or “blocker”.

The term “agent” as used herein includes any substance, molecule,element, compound, entity, or a combination thereof. It includes, but isnot limited to, e.g., protein, oligopeptide, small organic molecule,polysaccharide, polynucleotide, and the like. It can be a naturalproduct, a synthetic compound, or a chemical compound, or a combinationof two or more substances. Unless otherwise specified, the terms“agent”, “substance”, and “compound” can be used interchangeably.

The term “analog” is used herein to refer to a molecule thatstructurally resembles a molecule of interest but which has beenmodified in a targeted and controlled manner, by replacing a specificsubstituent of the reference molecule with an alternate substituent.Compared to the starting molecule, an analog may exhibit the same,similar, or improved utility. Synthesis and screening of analogs, toidentify variants of known compounds having improved traits (such ashigher potency at a specific receptor type, or higher selectivity at atargeted receptor type and lower activity levels at other receptortypes) is an approach that is well known in pharmaceutical chemistry.

Antagonists of interest include antibodies specific for one or moreadhesion molecules involved in leukocyte recruitment or trafficking tothe central nervous system. Also included are soluble receptors,conjugates of receptors and Fc regions, and the like. Generally, as theterm is utilized in the specification, “antibody” or “antibody moiety”is intended to include any polypeptide chain-containing molecularstructure that has a specific shape which fits to and recognizes anepitope, where one or more non-covalent binding interactions stabilizethe complex between the molecular structure and the epitope. Thearchetypal antibody molecule is the immunoglobulin, and all types ofimmunoglobulins (IgG, IgM, IgA, IgE, IgD, etc.), from all sources (e.g.,human, rodent, rabbit, cow, sheep, pig, dog, other mammal, chicken,turkey, emu, other avians, etc.) are considered to be “antibodies.”Antibodies utilized in the present invention may be polyclonalantibodies, although monoclonal antibodies are preferred because theymay be reproduced by cell culture or recombinantly, and may be modifiedto reduce their antigenicity.

Antibody fusion proteins may include one or more constant regiondomains, e.g. a soluble receptor-immunoglobulin chimera, refers to achimeric molecule that combines a portion of the soluble adhesionmolecule counterreceptor with an immunoglobulin sequence. Theimmunoglobulin sequence preferably, but not necessarily, is animmunoglobulin constant domain. The immunoglobulin moiety may beobtained from IgG1, IgG2, IgG3 or IgG4 subtypes, IgA, IgE, IgD or IgM,but preferably IgG1 or IgG3.

A straightforward immunoadhesin combines the binding region(s) of the“adhesin” protein with the hinge and Fc regions of an immunoglobulinheavy chain. Ordinarily nucleic acid encoding the soluble adhesionmolecule will be fused C-terminally to nucleic acid encoding theN-terminus of an immunoglobulin constant domain sequence, howeverN-terminal fusions are also possible. Typically, in such fusions theencoded chimeric polypeptide will retain at least functionally activehinge, CH2 and CH3 domains of the constant region of an immunoglobulinheavy chain. Fusions are also made to the C-terminus of the Fc portionof a constant domain, or immediately N-terminal to the CH1 of the heavychain or the corresponding region of the light chain. The precise siteat which the fusion is made is not critical; particular sites are wellknown and may be selected in order to optimize the biological activity,secretion or binding characteristics.

Antibodies that have a reduced propensity to induce a violent ordetrimental immune response in humans (such as anaphylactic shock), andwhich also exhibit a reduced propensity for priming an immune responsewhich would prevent repeated dosage with the antibody therapeutic arepreferred for use in the invention. These antibodies are preferred forall administrative routes, including intrathecal administration. Thus,humanized, chimeric, or xenogenic human antibodies, which produce lessof an immune response when administered to humans, are preferred for usein the present invention.

Chimeric antibodies may be made by recombinant means by combining themurine variable light and heavy chain regions (VK and VH), obtained froma murine (or other animal-derived) hybridoma clone, with the humanconstant light and heavy chain regions, in order to produce an antibodywith predominantly human domains. The production of such chimericantibodies is well known in the art, and may be achieved by standardmeans (as described, e.g., in U.S. Pat. No. 5,624,659, incorporatedfully herein by reference). Humanized antibodies are engineered tocontain even more human-like immunoglobulin domains, and incorporateonly the complementarity-determining regions of the animal-derivedantibody. This is accomplished by carefully examining the sequence ofthe hyper-variable loops of the variable regions of the monoclonalantibody, and fitting them to the structure of the human antibodychains. Alternatively, polyclonal or monoclonal antibodies may beproduced from animals which have been genetically altered to producehuman immunoglobulins, such as the Abgenix XenoMouse or the MedarexHuMAb® technology. Alternatively, single chain antibodies (Fv, asdescribed below) can be produced from phage libraries containing humanvariable regions.

In addition to entire immunoglobulins (or their recombinantcounterparts), immunoglobulin fragments comprising the epitope bindingsite (e.g., Fab′, F(ab′)₂, or other fragments) are useful as antibodymoieties in the present invention. Such antibody fragments may begenerated from whole immunoglobulins by ficin, pepsin, papain, or otherprotease cleavage. “Fragment” or minimal immunoglobulins may be designedutilizing recombinant immunoglobulin techniques. For instance “Fv”immunoglobulins for use in the present invention may be produced bylinking a variable light chain region to a variable heavy chain regionvia a peptide linker (e.g., poly-glycine or another sequence which doesnot form an alpha helix or beta sheet motif).

Small molecule agents encompass numerous chemical classes, thoughtypically they are organic molecules, e.g. small organic compoundshaving a molecular weight of more than 50 and less than about 2,500daltons. Candidate agents comprise functional groups necessary forstructural interaction with proteins, particularly hydrogen bonding, andtypically include at least an amine, carbonyl, hydroxyl or carboxylgroup, preferably at least two of the functional chemical groups. Thecandidate agents often comprise cyclical carbon or heterocyclicstructures and/or aromatic or polyaromatic structures substituted withone or more of the above functional groups. Candidate agents are alsofound among biomolecules including peptides, saccharides, fatty acids,steroids, purines, pyrimidines, derivatives, structural analogs orcombinations thereof.

Candidate agents are obtained from a wide variety of sources includinglibraries of synthetic or natural compounds. For example, numerous meansare available for random and directed synthesis of a wide variety oforganic compounds and biomolecules, including expression of randomizedoligonucleotides and oligopeptides. Alternatively, libraries of naturalcompounds in the form of bacterial, fungal, plant and animal extractsare available or readily produced. Additionally, natural orsynthetically produced libraries and compounds are readily modifiedthrough conventional chemical, physical and biochemical means, and maybe used to produce combinatorial libraries. Known pharmacological agentsmay be subjected to directed or random chemical modifications, such asacylation, alkylation, esterification, amidification, etc. to producestructural analogs. Test agents can be obtained from libraries, such asnatural product libraries or combinatorial libraries, for example.

Libraries of candidate compounds can also be prepared by rationaldesign. (See generally, Cho et al., Pac. Symp. Biocompat. 305-16, 1998);Sun et al., J. Comput. Aided Mol. Des. 12:597-604, 1998); eachincorporated herein by reference in their entirety). For example,libraries of GABA_(A) inhibitors can be prepared by syntheses ofcombinatorial chemical libraries (see generally DeWitt et al, Proc. Nat.Acad. Sci. USA 90:6909-13, 1993; International Patent Publication WO94/08051; Baum, Chem. & Eng. News, 72:20-25, 1994; Burbaum et al., Proc.Nat. Acad. Sci. USA 92:6027-31, 1995; Baldwin et al., J. Am. Chem. Soc.117:5588-89, 1995; Nestler et al., J. Org. Chem. 59:4723-24, 1994;Borehardt et al., J. Am. Chem. Soc. 116:373-74, 1994; Ohlmeyer et al.,Proc. Nat. Acad. Sci. USA 90:10922-26, all of which are incorporated byreference herein in their entirety.)

Candidate antagonists can be tested for activity by any suitablestandard means. As a first screen, the antibodies may be tested forbinding against the adhesion molecule of interest. As a second screen,antibody candidates may be tested for binding to an appropriate cellline, e.g. leukocytes or endothelial cells, or to primary tumor tissuesamples. For these screens, the candidate antibody may be labeled fordetection (e.g., with fluorescein or another fluorescent moiety, or withan enzyme such as horseradish peroxidase). After selective binding tothe target is established, the candidate antibody, or an antibodyconjugate produced as described below, may be tested for appropriateactivity, including the ability to block leukocyte recruitment to thecentral nervous system in an in vivo model, such as an appropriate mouseor rat epilepsy model, as described herein.

Currently available therapeutic agents for blocking leukocyterecruitment include polypeptide therapeutics, e.g. antibodies,monoclonal antibodies, receptor-Fc chimeric fusion proteins, etc., andsmall molecule-based drugs. There are now multiple clinically validatedanti-adhesion drugs. Small-molecule antagonists of adhesion moleculefunction can be categorized into three distinctive modes of action:ligand-mimetic competitive antagonists and allosteric antagonists or a Iallosteric antagonists.

Approved therapies comprise an antibody fragment, ReoPro™, and twosmall-molecule inhibitors, Integrilin™ and Aggrastat™. These structuresbuilt on previously published structures of an integrin binding to itsRGD based ligand. This information may yield additional routes to drugdiscovery that target medically relevant integrins.

The LFA-1/ICAM interaction is another key mediator of cell adhesionbetween leukocytes and vascular endothelium and, as both molecules areexpressed on leukocytes, they are involved in modulating immuneresponses. In particular, targeting the integrin α chain (CD11a) has ledto clinical success. The monoclonal antibody efaluzimab (Raptiva™)specifically recognizes the α chain of αLβ2. It inhibits the ability ofT cells to interact with Langerhans cells, endothelial cells andkeratinocytes. Antisense specifically directed at ICAM-1 (Alicaforsen™)has also been developed and is in clinical trials. Small-moleculeapproaches have been under active research and has provided a variety ofdistinct antagonists in pre-clinical studies.

The leukocyte integrin α4β1 interacts with its ligands VCAM andfibronectin. This is a key integrin-ligand interaction that allowsleukocytes to adhere strongly to vascular endothelium and triggersubsequent shape changes in the leukocyte, ultimately leading totransmigration. Antibodies and small-molecule antagonists are effectivein a wide range of animal models of inflammation. For example SB683699for multiple sclerosis is being tested for inflammation and hasdemonstrated positive effects. The anti-VLA4 monoclonal antibodyTysabri/Antegren™ is also in use. Another VLA4 antagonist is CDP323,which is currently in clinical trials. Also in clinical trials is theimmunoadhesin molecule YSPS.

Conditions of Interest

As used herein, the term “subject” encompasses mammals and non-mammals.Examples of mammals include, but are not limited to, any member of themammalian class: humans, non-human primates such as chimpanzees, andother apes and monkey species; farm animals such as cattle, horses,sheep, goats, swine; domestic animals such as rabbits, dogs, and cats;laboratory animals including rodents, such as rats, mice and guineapigs, and the like. The term does not denote a particular age or gender.The methods of the invention are useful in treating and preventingseizures, particularly recurrent seizures.

There are two kinds of seizure disorders: an isolated, nonrecurrentattack, such as may occur during a febrile illness or after head trauma,and epilepsy; a recurrent, paroxysmal disorder of cerebral functioncharacterized by sudden, brief attacks of altered consciousness, motoractivity, sensory phenomena, or inappropriate behavior caused byexcessive discharge of cerebral neurons. Seizures result from a focal orgeneralized disturbance of cortical function, which may be due tovarious cerebral or systemic disorders. Seizures may also occur as awithdrawal symptom after long-term use of alcohol, hypnotics, ortranquilizers. In many disorders, single seizures occur. However,seizures may recur at intervals for years or indefinitely, in which caseepilepsy is diagnosed.

Epilepsy is classified etiologically as symptomatic or idiopathic.Symptomatic indicates that a probable cause exists and a specific courseof therapy to eliminate that cause may be tried. Idiopathic indicatesthat no obvious cause can be found. Unexplained genetic factors mayunderlie idiopathic cases. The risk of developing epilepsy is 1% frombirth to age 20 yr and 3% at age 75 yr. Most persons have only one typeof seizure; about 30% have two or more types. About 90% have generalizedtonic-clonic. seizures. Absence seizures occur in about 25%. Complexpartial seizures occur in 18% (alone in 6%; with others in 12%).

Manifestations depend on the type of seizure, which may be classified aspartial or generalized. In partial seizures, the excess neuronaldischarge is contained within one region of the cerebral cortex. Ingeneralized seizures, the discharge bilaterally and diffusely involvesthe entire cortex. Sometimes a focal lesion of one part of a hemisphereactivates the entire cerebrum bilaterally so rapidly that it produces ageneralized tonic-clonic seizure before a focal sign appears.

Simple partial seizures consist of motor, sensory, or psychomotorphenomena without loss of consciousness. The specific phenomenonreflects the affected area of the brain. In complex partial seizures,the patient loses contact with the surroundings for 1 to 2 min. Mentalconfusion continues another 1 or 2 min after motor components of theattack subside. These seizures may develop at any age. Complex partialseizures most commonly originate in the temporal lobe but may originatein any lobe of the brain. Generalized seizures cause loss ofconsciousness and motor function from the onset. Such attacks often havea genetic or metabolic cause. They may be primarily generalized(bilateral cerebral cortical involvement at onset) or secondarilygeneralized (local cortical onset with subsequent bilateral spread).Types of generalized seizures include infantile spasms and absence,tonic-clonic, atonic, and myoclonic seizures.

Absence seizures consist of brief, primarily generalized attacksmanifested by a 10- to 30-sec loss of consciousness and eyelidflutterings, with or without loss of axial muscle tone. Affectedpatients do not fall or convulse; they abruptly stop activity and resumeit just as abruptly after the seizure. Generalized tonic-clonic seizurestypically begin with an outcry; they continue with loss of consciousnessand falling, followed by tonic, then clonic contractions of the musclesof the extremities, trunk, and head. Urinary and fecal incontinence mayoccur. Seizures usually last 1 to 2 min. Secondarily generalizedtonic-clonic seizures begin with a simple partial or complex partialseizure. Atonic seizures are brief, primarily generalized seizures inchildren. They are characterized by complete loss of muscle tone andconsciousness. The child falls or pitches to the ground, so thatseizures pose the risk of serious trauma, particularly head injury.Myoclonic seizures are brief, lightning-like jerks of a limb, severallimbs, or the trunk. They may be repetitive, leading to a tonic-clonicseizure. There is no loss of consciousness.

Conventional treatment focuses on the use of anticonvulsant drugs. Forgeneralized tonic-clonic seizures, phenytoin, carbamazepine, orvalproate is the drug of choice. For partial seizures, treatment beginswith carbamazepine, phenytoin, or valproate. If seizures persist despitehigh doses of these drugs, gabapentin, lamotrigine, or topiramate may beadded. For absence seizures, ethosuximide orally is preferred. Valproateand clonazepam orally are effective, but tolerance to clonazepam oftendevelops. Acetazolamide is reserved for refractory cases. Atonicseizures, myoclonic seizures, and infantile spasms are difficult totreat. Valproate is preferred, followed, if unsuccessful, by clonazepam.Ethosuximide is sometimes effective, as is acetazolamide (in dosages asfor absence seizures). Phenytoin has limited effectiveness. Forinfantile spasms, corticosteroids for 8 to 10 wk are often effective.Carbamazepine may make patients with primary generalized epilepsy andmultiple seizure types worse.

Methods

In the broadest sense, methods are provided for inhibiting recurrentseizures, including those associated with epilepsy, in a mammalian host.The host is generally a mammal, e.g. mouse, rat, monkey, etc. and inmany embodiments is a human. An inhibitor of leukocyte recruitment ortrafficking is administered to a mammalian host, where theadministration may follow a seizure, or in the case of a patient withknown recurrent disease, may be administered following diagnosis. Inaddition to seizure activity, the patient may be screened for evidenceof CNS inflammation, e.g. by MRI, etc.

The inhibitor of leukocyte recruitment or trafficking may beadministered in a single dose, or may be administered at regularintervals, e.g. at least weekly, daily, or every two days, and may beadministered twice daily, or more often, e.g. around about every 4-8hours. Typically, after administration the blocker reaches therapeuticlevels in the brain vasculature at least transiently, e.g. for aroundabout 1 minute, at least about 5 minutes, at least about 30 minutes, atleast about 1 hour, or more.

Administration of the treatment is maintained for a period of timesufficient to effect a change in CNS leukocyte recruitment ortrafficking. Such treatment may involve dosing for at least about oneweek, at least about two weeks; at least about 3 weeks; at least aboutone month; at least about two months; at least about four to six months;or longer, for example at least about one or more years. For extendedtreatment; e.g. treatment of one or more years, a schedule may involveintermittent periods, such as one week on and one week off; two weeks onand two weeks off; one week in a month, etc.

Patients that can benefit from the present invention may be of any ageand include adults and children, e.g. young adults. Children, e.g.neonate, infant, early childhood, adolescent, etc. in particular maybenefit prophylactic treatment. Children suitable for prophylaxis can beidentified by genetic testing for predisposition, e.g. by chromosometyping; by family history, or by other medical means. As is known in theart, dosages may be adjusted for pediatric use. Anti-adhesion therapiesmay also help prevent the occurrence of epilepsy following brain insultsassociated with inflammation such as traumatic brain injury, forinstance in military personnel in war zones where seizures and epilepsypresent a significant health problem.

The inhibitor of leukocyte recruitment or trafficking is generallyadministered to the host as a pharmaceutical composition that includesan effective amount of the inhibitor of leukocyte recruitment ortrafficking in a pharmaceutically acceptable vehicle. In the subjectmethods, the active agent(s) may be administered to the host using anyconvenient means capable of resulting in the desired improvement ofseizures.

Therapeutic agents can be incorporated into a variety of formulationsfor therapeutic administration by combination with appropriatepharmaceutically acceptable carriers or diluents, and may be formulatedinto preparations in solid, semi-solid, liquid or gaseous forms, such astablets, capsules, powders, granules, ointments, solutions,suppositories,. injections, inhalants, gels, microspheres, and aerosols.As such, administration of the compounds can be achieved in variousways, including oral, buccal, rectal, parenteral, intraperitoneal,intradermal, transdermal, intrathecal, nasal, intracheal, etc.,administration. The active agent may be systemic after administration ormay be localized by the use of regional administration, intramuraladministration, or use of an implant that acts to retain the active doseat the site of implantation.

Pharmaceutical compositions can include, depending on the formulationdesired, pharmaceutically-acceptable, non-toxic carriers of diluents,which are defined as vehicles commonly used to formulate pharmaceuticalcompositions for animal or human administration. The diluent is selectedso as not to affect the biological activity of the combination. Examplesof such diluents are distilled water, buffered water, physiologicalsaline, PBS, Ringer's solution, dextrose solution, and Hank's solution.In addition, the pharmaceutical composition or formulation can includeother carriers, adjuvants, or non-toxic, nontherapeutic, nonimmunogenicstabilizers, excipients and the like. The compositions can also includeadditional substances to approximate physiological conditions, such aspH adjusting and buffering agents, toxicity adjusting agents, wettingagents and detergents. The composition can also include any of a varietyof stabilizing agents, such as an antioxidant for example.

Further guidance regarding formulations that are suitable for varioustypes of administration can be found in Remington's PharmaceuticalSciences, Mace Publishing Company, Philadelphia, Pa., 17th ed. (1985).For a brief review of methods for drug delivery, see, Langer, Science249:1527-1533 (1990).

Toxicity and therapeutic efficacy of the active ingredient can bedetermined according to standard pharmaceutical procedures in cellcultures and/or experimental animals, including, for example,determining the LD₅₀ (the dose lethal to 50% of the population, or forthe methods of the invention, may alternatively by the kindling dose)and the ED₅₀ (the dose therapeutically effective in 50% of thepopulation). The dose ratio between toxic and therapeutic effects is thetherapeutic index and it can be expressed as the ratio LD₅₀/ED₅₀.Compounds that exhibit large therapeutic indices are preferred.

The data obtained from cell culture and/or animal studies can be used informulating a range of dosages for humans. The dosage of the activeingredient typically lines within a range of circulating concentrationsthat include the ED₅₀ with low toxicity. The dosage can vary within thisrange depending upon the dosage form employed and the route ofadministration utilized.

The pharmaceutical compositions described herein can be administered ina variety of different ways. Examples include administering acomposition containing a pharmaceutically acceptable carrier via oral,intranasal, rectal, topical, intraperitoneal, intravenous,intramuscular, subcutaneous, subdermal, transdermal, intrathecal, andintracranial methods.

For oral administration, the active ingredient can be administered insolid dosage forms, such as capsules, tablets, and powders, or in liquiddosage forms, such as elixirs, syrups, and suspensions. The activecomponent(s) can be encapsulated in gelatin capsules together withinactive ingredients and powdered carriers, such as glucose, lactose,sucrose, mannitol, starch, cellulose or cellulose derivatives, magnesiumstearate, stearic acid, sodium saccharin, talcum, magnesium carbonate.Examples of additional inactive ingredients that may be added to providedesirable color, taste, stability, buffering capacity, dispersion orother known desirable features are red iron oxide, silica gel, sodiumlauryl sulfate, titanium dioxide, and edible white ink. Similar diluentscan be used to make compressed tablets. Both tablets and capsules can bemanufactured as sustained release products to provide for continuousrelease of medication over a period of hours. Compressed tablets can besugar coated or film coated to mask any unpleasant taste and protect thetablet from the atmosphere, or enteric-coated for selectivedisintegration in the gastrointestinal tract. Liquid dosage forms fororal administration can contain coloring and flavoring to increasepatient acceptance.

Formulations suitable for parenteral administration include aqueous andnon-aqueous, isotonic sterile injection solutions, which can containantioxidants, buffers, bacteriostats, and solutes that render theformulation isotonic with the blood of the intended recipient, andaqueous and non-aqueous sterile suspensions that can include suspendingagents, solubilizers, thickening agents, stabilizers, and preservatives.

The components used to formulate the pharmaceutical compositions arepreferably of high purity and are substantially free of potentiallyharmful contaminants (e.g., at least National Food (NF) grade, generallyat least analytical grade, and more typically at least pharmaceuticalgrade). Moreover, compositions intended for in vivo use are usuallysterile. To the extent that a given compound must be synthesized priorto use, the resulting product is typically substantially free of anypotentially toxic agents, particularly any endotoxins, which may bepresent during the synthesis or purification process. Compositions forparental administration are also sterile, substantially isotonic andmade under GMP conditions.

The compositions of the invention may be administered using anymedically appropriate procedure, e.g. intravascular (intravenous,intraarterial, intracapillary) administration, injection into thecerebrospinal fluid, intracavity or direct injection in the brain.Intrathecal administration maybe carried out through the use of anOmmaya reservoir, in accordance with known techniques. (F. Balis et al.,Am J. Pediatr. Hematol. Oncol. 11, 74, 76 (1989).

The effective amount of a therapeutic composition to be given to aparticular patient will depend on a variety of factors, several of whichwill be different from patient to patient. A competent clinician will beable to determine an effective amount of a therapeutic agent toadminister to a patient. Dosage of the agent will depend on thetreatment, route of administration, the nature of the therapeutics,sensitivity of the patient to the therapeutics, etc. Utilizing LD₅₀animal data, and other information, a clinician can determine themaximum safe dose for an individual, depending on the route ofadministration. Utilizing ordinary skill, the competent clinician willbe able to optimize the dosage of a particular therapeutic compositionin the course of routine clinical trials. The compositions can beadministered to the subject in a series of more than one administration.For therapeutic compositions, regular periodic administration willsometimes be required, or may be desirable. Therapeutic regimens willvary with the agent.

The invention also provides a pharmaceutical pack or kit comprising oneor more containers filled with one or more of the ingredients of thepharmaceutical compositions of the invention. Associated with suchcontainer(s) can be a notice in the form prescribed by a governmentalagency regulating the mariufacture, use or sale of pharmaceuticals or *biological products, which notice reflects approval by the agency ofmanufacture, use or sale for human administration.

In another aspect of the invention, candidate agents are screened forthe ability to inhibit leukocyte recruitment or trafficking and toprevent seizure recurrence. Such compound screening may be performedusing an in vitro model, a genetically altered cell or animal, orpurified proteins, particularly the human leukocyte adhesion molecules,or cells expressing such molecules. A wide, variety of assays may beused for this purpose. In one embodiment, compounds that are active inbinding assays with the adhesion molecules, or are predicted to beantagonists of the adhesion molecules are then tested in an in vitroculture system. Alternatively, candidate agents are tested forantagonist activity, and may then be assessed in animal models fortreatment of seizures.

Compounds that are initially identified by any screening methods can befurther tested to validate the apparent activity. The basic format ofsuch methods involves administering a lead compound identified during aninitial screen to an animal that serves as a model for humans and thendetermining the effects on CNS and seizures. The animal models utilizedin validation studies generally are mammals. Specific examples ofsuitable animals include, but are not limited to, primates, mice, andrats.

Those of skill will readily appreciate that dose levels can vary as afunction of the specific compound, the severity of the symptoms and thesusceptibility of the subject to side effects. Preferred dosages for agiven compound are readily determinable by those of skill in the art bya variety of means.

EXPERIMENTAL

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the subject invention, and are not intended to limit thescope of what is regarded as the invention. Efforts have been made toensure accuracy with respect to the numbers used (e.g. amounts,temperature, concentrations, etc.) but some experimental errors anddeviations should be allowed for. Unless otherwise indicated, parts areparts by weight, molecular weight is average molecular weight,temperature is in degrees centigrade; and pressure is at or nearatmospheric.

Example 1

Experimental and clinical data indicate that the occurrence of repeatedseizures can lead to a chronic epileptic condition. In the last decade,vascular alterations and the cytokines, have been discussed in relationto the pathogenesis of epilepsy, suggesting a potential role forinflammatory mechanisms of tissue damage. Leukocyte recruitment is botha hallmark of and a point of potential therapeutic intervention ininflammation, yet white cell recruitment has not been examined afterseizures or in epilepsy.

To determine whether human epilepsy is associated with increasedleukocyte infiltration in the CNS, we analyzed brain specimens from 10long-term epileptics with no concurrent inflammatory brain diagnoses, 10age-matched controls with no neurological diseases and 10 controls withnon-inflammatory neurological diseases (NIND) (Table 1A-C).Immunohistologic observations revealed leukocytes in the parenchyma ofepileptic brains, but not in control NIND subjects (FIGS. 1D-F and 1A-Crespectively). Cells expressing the leukocyte common antigen (CD45) weredetectable both in blood vessels and in the brain parenchyma in theepileptic group (FIG. 1D, G), whereas in NIND brains CD45+ cells wereconfined to the lumena of vessels (FIG. 1A, G). Most of the paranchymalcells were perivascular in location, suggesting recent recruitment. Mostimportantly, granulocytes and T cells were observed in the brains of allpatients with epilepsy. Polymorphonuclear leukocytes (PMNs), identifiedby myeloperoxidase staining, were much more frequent in the parenchymain brain specimens of epileptic group (FIG. 1 E, 1H) when compared withcontrol brains (FIG. 1 B, 1H). CD3+ T cells were also more frequent inthe parenchyma of epileptic subjects (FIG. 1F and 1I versus controlbrain, FIG. 1C, 1I). Morphometric analyses are summarized in FIG. 1G-I.Brain sections from patients with no neurological disease were similarto those from NIND patients (N=10). These observations show thatleukocytes are recruited to the brain vascular and into the surroundingparenchyma of patients with seizures and suggest an ongoing low levelinflammatory process. We hypothesized that leukocyte recruitment mightexacerbate the underlying seizure mechanisms.

TABLE 1 Human subjects¹. Patient Gender Age Epileptic Condition A P. D.A. F 48 epileptic P. E. F 41 epileptic C. R. M 46 epileptic in therapywith gardenale M. K. M 23 Generalized epilepsy A. P. K. M 33 epilepticafter a traffic crash (2 years ago) M. G. M 42 epileptic in cerebralarteriovenous malformation at the right hemisphere S. S. M 50 epilepticin therapy with drugs P. N. M 74 epileptic in therapy with drugs C. V. M67 epileptic in therapy with drugs G. G  M 27 epileptic in therapy withdrugs B O. E. F 48 none B. R. F 41 none B. D. M 46 none M. F. M 23 noneC. G. M 33 none V. F. M 42 none B. P. M 50 none B. M. M 74 none V. A. M67 none P. F. M 27 none C Patient Gender Age NIND V. G. M 89Multiinfarctual Demenza D. L. M 87 Parkinson Disease R. T. F 76Parkinson Disease B. C. F 88 Parkinson Disease P. N. M 79 ParkinsonDisease P. M. M 77 Parkinson Disease D. M. M 78 Parkinson Disease G. D.M 83 Parkinson Disease T. I. F 65 Parkinson Disease M. L. M 72 ParkinsonDisease ¹Cortical samples were obtained from 10 epileptic patients (A),10 relative age-matched controls (B) and 10 controls withnon-inflammatory neurological diseases (NIND) (C). No known cerebralinflammatory diseases were diagnosed as cause of death or beforedecease. All the brain samples were collected and stored at theDepartment of Medicine and Public Health, Section of Forensic Medicine,University of Insubria, Varese, Italy.

To test this hypothesis, we turned to a mouse model of epilepsy.Systemic administration of pilocarpine induces limbic seizures inrodents, mimicking temporal lobe epilepsy, the most frequent type ofepilepsy in humans. Pilocarpine-induced status epilepticus (SE) ischaracterized by continuous seizures lasting 1-2 h in our experimentalmodel (in other experimental models, for instance in rats, seizures lastup to 24 h), and results in brain injury, leading after a latency phaseof 1-2 weeks to establishment of epilepsy characterized by recurrentspontaneous seizures. In addition to hippocampal damage, recent evidencesuggests that pilocarpine-induced seizures cause widespread cortical andsubcortical lesions.

We looked for vascular modifications as signs of inflammation after SEin mice. In agreement with previous histochemical studies indicative ofseizure-induced vascular permeability, contrast agent perfusion followedby MRI revealed focal loss of the of blood brain barrier 6 hours afterSE, with a hyperintense signal indicating vascular leakage in theparietal neocortex (FIG. 12 wt). In addition, there was a 30% increasein the diameter of cortical vessels 6 h post SE (FIG. 13). These resultsare consistent with a condition of acute inflammation affecting brainvessels shortly after seizure activity.

Induction of vascular adhesion molecules involved in leukocyterecruitment is a hallmark of local inflammation. To assess adhesionmolecule induction, fluorescence-labeled antibodies to ICAM-1, VCAM-1,P-selectin, E-selectin or MAdCAM-1 were injected iv into mice at varioustimes after pilocarpine-induced SE (FIG. 2 and Table 2). As shown inFIG. 2A, anti-VCAM-1 mAb accumulated at high levels on arteriolar andvenular endothelium in the CNS after seizure activity (FIG. 2A, Table2). ICAM-1 was present at low levels even in control mice, butexpression of VCAM-1 was induced following seizure induction, with thehighest levels observed at 24 h and 7d post-SE (Table 2). Importantly,pharmacologic suppression of SE by administration of Diazepam prior topilocarpine injection largely abrogated the upregulation of VCAM-1 (FIG.2A), suggesting that seizure activity itself contributes to highexpression of VCAM-1 in brain vessels. In addition, we observed thatanti-P-selectin and anti-E-selectin mAbs accumulated in venularendothelium at 6 h and 24 h after seizures (FIG. 2A and Table 2).Together, these results show that intense seizure activity leads toproinflammatory changes in CNS endothelium, which could supportleukocyte recruitment and consequent amplification of inflammatorydamage.

TABLE 2 Expression of adhesion molecules post-SE² hours/days postinduction of seizures 6 h 24 h 7 days 30 days Control mAb − − − −MAdCAM-1 − − − − VCAM-1 ++ +++ +++ + ICAM-1 + + ++ + P-selectin + ++ ±ND E-selectin + ++ + ND ²Epilepsy was induced in C56BI/6 mice asdescribed at Materials and Methods section and positivity for adhesionmolecules was evaluated at different time points after the induction ofSE. Two mice per time-point for each mAb were used. Blinded evaluationshowed that cortical brain vessels were positive for VCAM-1, ICAM-1,P-selectin and E-selectin. No positivity was observed with control mAband anti-MAdCAM-1 mAb (−). ± some venules were positive while othervenules were apparently negative; +, low positivity; ++ mediumpositivity; +++, high positivity; ND, not determined.

We next asked if leukocytes are recruited into the CNS after SE. PMNsand Th1 lymphocytes were labeled with iron particles and tracked by MRIafter transfusion iv into recipients either 2 h (for PMNs) or 24 h (forTh1 cells) after pilocarpine injection. 24 h after cell transfer,localization of cells in the neocortex, hippocampus and thalamus wasrevealed by the appearance of hypointense spots indicating the presenceof iron particles (FIG. 2B shows focal neutrophil localization; 2Cillustrates Th1 cell localization). No localization of injected cellswas detected in the brains of control mice). Histochemical staining ofbrains after MRI confirmed that the ferric iron particles wereassociated with labeled cells (FIG. 2D). In independent studies, weinjected fluorescence-labeled PMNs 6 h after induction of SE. 24 h laterwe observed transferred as well as endogenous Gr-1 positive cells in thebrain parenchyma. (FIG. 2E, F). Moreover, CD3 staining and confocalmicroscopy revealed endogenous T cells localized perivascularly 24 hafter SE (FIG. 2H). Since pilocarpine does not induce adhesion ofleukocytes per se (FIG. 14), the findings suggest that leukocyterecruitment was enhanced as a result of vascular changes inducedfollowing SE.

To visualize leukocyte interactions with the brain microvasculaturedirectly, we infused fluorescence labeled PMNs or lymphocytes iv, andmonitored their behavior using intravital microscopy. Injected PMNsinteracted efficiently, displaying rolling and arrest in brain venulesin mice both 6 and 24 h after SE (FIG. 3A-C). The rolling fraction wassimilar at 6 h and at 24 h, while the fraction of cells that arrestedwas 2.6 times higher at 6 h, indicating that PMNs are able to stick moreefficiently to brain endothelium early after SE. Resting lymphocytesfrom peripheral lymph nodes did not interact, suggesting that lymphocyteactivation might be a prerequisite for the seizure-induced adhesion(FIG. 3A), as it is for lymphocyte-endothelial adhesion in models ofexperimental allergic encephalomyelitis. Indeed, activated lymphocyteswith a Th1 phenotype rolled and stuck efficiently in CNS vessels afterseizure activity. Th1 cells interacted more efficiently at 24 h than at6 h after seizures, with a 3 fold increase of rolling cells and a 4 foldincrease of firmly adherent cells at the later time point. The earlyarrest of PMN and later enhanced lymphocyte interactions are consistentwith progression from acute to subacute inflammation during the 24 hperiod after SE-induced damage (FIG. 3A, B). Analysis of rollingvelocities (Vroll) and the frequency distribution of Vroll in velocityclasses is provided at FIG. 4 and Tables 3 and 4. No rolling or stickingof PMNs or Th1 cells was seen in normal mice not injected withpilocarpine. Interestingly, in vitro polarized Th2 cells did not roll orstick in brain vessels, suggesting that activated brain endothelium maypreferentially recruit Th1 cells after seizures (FIG. 3A).

TABLE 3 Diameter, hemodynamics and rolling velocities in cerebralvenules at 6 h post-SE³ Cell type PMNs Th1 cells Th2 cells PLN cells 6HOURS post-SE 6/5 4/5 3/2 3/2 Number of venules/ animals animalsDiameter (μm) 72 ± 21 52 ± 34 68 ± 26 58 ± 44 V_(fast) (μm/s) 4578 ±1744 3469 ± 2779 3889 ± 1875 4421 ± 1988 V_(m) (μm/s) 2303 ± 876  1786 ±1356 1836 ± 885  2087 ± 938  WSS (dyne/cm²) 7.2 ± 2.4 7.8 ± 0.8 8.7 ±1.7 8.9 ± 1.8 Median V_(roll) (μm/s) 40 18.2 0 0 ³Venules were analyzedby individual velocity measurement of at least 20 consecutivenon-interacting PLN cells, Th1, Th2 cells or PMNs in each venule. Thevelocity of the fastest cell in the sample (V_(fast)) was used todetermine the mean blood flow velocity (V_(m)). Venular wall shear rateand wall shear stress (WSS) and the percentage of rolling and arrestedcells were calculated as described at Materials and Methods section. Thevelocity of 10 rolling cells/venule was measured by digitalframe-by-frame analysis of videotapes. V_(roll) are presented as median.Data are arithmetic mean ± SD

TABLE 4 Diameter, hemodynamics and rolling velocities in cerebralvenules at 24 h post-SE⁴ Cell type PMNs Th1 cells 24 HOURS post-SE 7/44/3 Number of venules/animals Diameter (μm) 57 ± 25 71.6 ± 63.4 V_(fast)(μm/s) 5528 ± 2141  4745 ± 117.4 V_(m) (μm/s) 2792 ± 1061 2464 ± 61.5 WSS (dyne/cm²) 10.4 ± 2.9  11.5 ± 10.4 Median V_(roll) (μm/s) 35.5 46.2⁴Parameters were calculated as described for Table 3.

The induction of VCAM-1 suggested that leukocyte ligands, integrin α4β1(receptor for VCAM1) might mediate leukocyte recruitment followingseizure activity. Although classically associated with lymphocyte andmonocyte adhesion, α4β1 also participates in PMN recruitment, and wefirst examined the effects of antibodies to VCAM-1 and α4 integrin onPMN interactions with the brain vasculature. As shown in FIG. 3, rollinginteractions of PMNs after SE were dramatically inhibited by antibodyblockade of VCAM-1 and α4 integrin (FIG. 3D). Moreover, these antibodiescompletely blocked sticking of PMN to vessels 6 h postseizure.Neutrophil sticking was also inhibited by 90% at the later time point,24 h after SE (FIG. 3F). Anti-MAdCAM-1 mAb had no significant effect,excluding a role for α4β7 integrin and MAdCAM-1 adhesive interactions(FIG. 3F).

It has been previously considered that neutrophils do not express α4β1integrin, a molecule implicated in the recruitment of monocytes,lymphocytes and eosinophils to sites of inflammation. However, in thelast years consistent data from various laboratories demonstrate thatneutrophils are indeed able to express the α4 integrin and use thisalternative mechanism for adhesion and migration in experimental modelsof inflammation or in human disease.

Rolling of Th1 cells was also significantly reduced by VCAM-1 or α4blockade 6 h after SE but the inhibition was lower than that observed inPMNs (FIG. 3E). Arrest of Th1 cells was dramatically blocked at 6 hsuggesting that VCAM-1 plays a critical role also for the earlyrecruitment of lymphocytes. Notably, 95% of Th1 cell rolling was blockedby anti-PSGL-1, suggesting that PSGL-1 is a key molecule in therecruitment of lymphocytes after seizures. Sticking, but not rolling, ofTh1 cells was totally blocked at 24 h, revealing a central role forVCAM-1 and PSGL-1 in the arrest of activated lymphocytes in CNS vesselspost-SE (FIG. 3G). Taken together these results show that the integrinα4β1 and the selectin ligand PSGL-1 are critically involved in therecruitment of leukocytes to cerebral vessels following seizureactivity. We reasoned that, if leukocyte recruitment is a significantcontributor to the pathogenesis of seizure activity, then inhibition ofα4β1 might alter the course of pilocarpine-induced SE and the subsequentdevelopment of chronic epilepsy.

We next investigated the effects of α4 integrin blockade on SE and theevolution of epilepsy (FIGS. 5 and 6). To assess the ability of antibodytherapy to alter the course of established SE and to influence thedevelopment of subsequent epilepsy, we induced seizure activity withpilocarpine and injected anti-α4 integrin mAb i.p. 1 hour after SE onset(stage 5 of Racine's Scale). Treatment after onset had no effect on theduration of the induced status epilepticus, but continuous videomonitoring revealed a dramatic reduction in visible convulsions over thefollowing 20 days (FIG. 5A, C, D). The frequency of convulsions overthis period fell from 6.13±1.82 per day in the epileptic control group(SD, N=12 per group) to only 1.93±1.43 (P<0.001) in the anti-a4-treatedmice (FIG. 5C).

EEG telemetry (FIG. 6A, C) confirmed the behavioral data by showing adrastic reduction in the number of abnormal electrical events and intotal seizure time after SE in mice treated with anti-α4 integrin mAbwhen compared with control animals (FIG. 6D: Mean number ofseizures/mouse: control epileptic group: 47±6 (SD, N=12 per group);anti-α4 integrin-treated group: 10±3, P<0.001; FIG. 6E: average seizureduration/mouse: epileptic: 1764±35 sec; anti-α4 integrin treatment:409±21 sec, P<0.001). Mice treated with a control mAb showed no effecton the duration of SE and establishment of chronic disease. Cognitiveevaluation based on enriched open-field exploration revealed thatanti-α4 treated animals exhibited a slight reduction of explorationbehavior compared to normal animals, but a significant preservation ofthe behavior compared to epileptic mice (FIG. 5E, Table 5).

TABLE 5 Enriched open field test in different experimental groups.Episode Frequency (events/10 min) Mean SEM center Controls  27.3^(a,e)3.8 Epileptics  14^(a,b,c) 1.77 Anti-α4 2 h before SE  26.1^(b,d) 2.54Anti-α4 1 h after SE  19.9^(c,d,e) 4.1 inter- Controls 135.9^(f) 6.2mediate Epileptics  96.1^(f,g,h) 3.85 Anti-α4 2 h before SE 127.7^(g)4.74 Anti-α4 1 h after SE 123.7^(h) 3.1 borders Controls  90.7^(i) 3Epileptics  36.5^(i,j) 4.2 Anti-α4 2 h before SE  90.5^(j) 2.1 Anti-α4 1h after SE  57.3 1.9 ^(a)p < .001; ^(b)p < .001; ^(c)p < .05; ^(d)p <.05; ^(e)p < .05; ^(f)p < .001; ^(g)p < .001; ^(h)p < .001; ^(i)p <.001; ^(j)p < .001 Cognitive evaluation was based on enriched open-fieldexploration. Epileptic animals have been previously reported toselectively decrement explorative behavior of new objects placed in thecenter of the arena. The cognitive evaluation revealed that anti-α4treated animals before SE induction exhibited a normal explorationbehavior compared to control animals (PBS injected mice). Mice treated 1h after SE onset displayed a significant reduction of new objectsexploration (center) when compared to control animals, but a significantimprovement of the behavior when compared to epileptic animals. Post-hocstatistical values (ANOVA) are reported at the bottom of the Table.

The results obtained with anti-α4 integrin therapy were furtherconfirmed by treating the mice with 150 μg anti-VCAM-1 mAb (M.K.2.7)/day (12 mice/group), starting 1 h after the onset of SE(anti-VCAM-1 mAb administration was performed at the same time points asdescribed for FIG. 5). The results clearly showed a dramatic reductionof the daily frequency of convulsions (from and 6.9±1.9 in the controlepileptic group to 1.3±0.7 in the anti-VCAM-1 treated group) and totalnumber of convulsions (80% reduction from 81.6 in the control epilepticgroup versus 16.8 in the ant-VCAM-1 treated group) over a period ofobservation of 30 days. Moreover, mice treated with anti-VCAM-1 mAbshowed a significant preservation of normal behavior when compared withmice treated only with vehicle or with control mAb.

Finally, we evaluated the preventive effect of anti-α4 integrin mAbtreatment. Strikingly, treatment with 200 μg anti-α4 integrin mAb i.p. 2h before injection of pilocarpine completely prevented seizures (FIGS. 5and 6). Behavioral observations included sporadic tremors and oralmastication (stage 2 of the Racine's Scale¹⁸) in anti-α4 integrintreated mice in the first hour after pilocarpine injection, but nofurther tremors and no convulsions were detected during the successive20 days (FIG. 5 A, C, D). Moreover, anti-α4 integrin treated micedisplayed no EEG alterations following pilocarpine-injection in thetime-window analyzed (FIG. 6 A, B, D, E). α4 integrin blockade alsoprevented weight loss during the observation period (FIG. 5B). Micetreated with a control mAb showed no effect on the induction of SE andestablishment of chronic disease (FIG. 7 and Table 6). Cognitiveevaluation based on enriched open-field behavior revealed that animalsreceiving preventive treatment with anti-α4 integrin mAb behave likecontrol (non-pilocarpine injected) mice with normal exploration of thecentral zone in a field characterized by new objects (FIG. 5E, Table 5).

Example 2

The increased expression of ICAM-1 on brain endothelium after seizuressuggested that ICAM-1 and beta 2 integrins might mediate the leukocyterecruitment following seizure activity. To test this hypothesis, weexamined the effects of antibodies to ICAM-1 and LFA-1 integrin on PMNinteractions with the brain vasculature. As shown in FIG. 8, rollinginteractions of PMNs after SE were significantly inhibited by blockadeof ICAM-1 or LFA-1 integrin (inhibition of 60% of rolling for bothmAbs). Moreover, the antibodies drastically blocked sticking of PMNs tovessels 6 h postseizure (blockade of 65% of adhesion by anti-alphaL mAband of 62% by anti-ICAM-1 mAb). Neutrophil rolling and sticking was alsostrongly inhibited by anti-ICAM-1 mAb or anti-LFA-1 mAbs at the latertime point, 24 h after SE. We conclude that LFA-1 integrin and ICAM-1have an important role in the recruitment of PMNs to cerebral vesselsfollowing seizure activity.

In mouse models of pilocarpine-induced status epilepticus (SE) andepilepsy, SE and repeated seizures induced expression of ICAM-1 on CNSvessels lasting for at least 30 days post SE (FIG. 2A). Therapeutictreatment of mice with anti-LFA-1 mAb (TIB 213) or with anti-ICAM-1(Y.N. 1.7) leads to a drastic reduction in seizure activity (FIG. 9).The frequency of convulsions over the observation period fell from6.8±2.1 per day in the epileptic control group (SD, N=10 per group) toonly 1.6±1 (P<0.001) in the anti-LFA-1 treated mice and to 1.6±0.7 (FIG.9A). In addition the total number of convulsions fell drastically from78 in the epileptic control group to 22 in the anti-LFA-1 treated miceand to 19 in the anti-ICAM-1-treated group (FIG. 9B). Preventiveadministration of anti-LFA-1 therapy inhibits induction of SE andcompletely blocks recurrent seizures and development of epilepsy in30-40% of animals. The frequency of convulsions over the observationperiod fell from 6.5±1.8 per day in the epileptic control group (SD,N=10 per group) to 1.8±0.5 (P<0.001) in the anti-LFA-1 treated mice andto 0.55 ±1.1 (FIG. 9A). In addition the total number of convulsions felldrastically from 82 in the epileptic control group to 19 in theanti-LFA-1 treated mice and to 7 in the anti-ICAM-1-treated group (FIG.9B). Furthermore, anti-LFA-1 and anti-ICAM-1 treated mice showed asignificant improvement of open-field exploration when compared tountreated epileptic-mice (FIG. 9C). Mice treated with a control mAbshowed no effect on the induction of SE and establishment of chronicdisease (FIG. 7 and Table 6). The results show a critical role for beta2integrins and ICAM-1 in the induction of seizures and epilepsy.

TABLE 6 Enriched open field test in control mAb. Episode Frequency(events/10 min) Mean SEM center Epileptics 14 1.77 Control mAb 12.1 1.3intermediate Epileptics 96.1 3.85 Control mAb 75.3 9.1 bordersEpileptics 36.5 4.2 Control mAb 31.1 4.7 Cognitive evaluation was basedon enriched open-field exploration in epileptic versus controlmAb-treated mice.

Example 3

The upregulation of P- and E-selectin on brain endothelium afterseizures suggested that PSGL-1 and endothelial selectins mediate theleukocyte recruitment following seizure activity. We examined theeffects of antibodies to PSGL-1, and P-selectin on PMN interactions withthe brain vasculature. As shown in FIG. 8, rolling interactions of PMNsafter SE were almost completely inhibited by blockade of ICAM-1 or LFA-1integrin (inhibition of ˜90% of rolling for both mAbs). Moreover, theantibodies abolished sticking of PMNs to vessels 6 h postseizure. Th1cells rolling and sticking was also strongly inhibited by anti-PSGL-1mAb or anti-P-selectin mAbs at 6 h after SE). We conclude that PSGL-1and P-selectin are critically involved in the recruitment of leukocytesto cerebral vessels following seizure activity. We reasoned that, ifleukocyte recruitment is a significant contributor to the pathogenesisof seizure activity, then inhibition of PSGL-1 will alter the course ofpilocarpine-induced SE and the subsequent development of chronicepilepsy.

Although antibody should be excluded from the CNS by the BBB prior tostatus epilepticus, we could not rule out the formal possibility thatanti-α4 or anti-αL treatment have direct effects on nervous tissue. Toaddress this issue and to assess the role of additional adhesionmechanisms, we next evaluated the effects of genetic deficiency in theleukocyte-specific adhesion molecule, PSGL1. PSGL1 is a leukocyte mucinthat participates in the recruitment of leukocytes to the inflamed brainby mediating leukocyte interactions with endothelial selectins. PSGL-1binds both E- and P-selectin in vivo, and antibodies to PSGL-1 inhibitinteractions of leukocytes with inflamed vessels in a number of animalmodels.

Two leukocyte-expressed α-1,3-fucosyltransferases (FucTs), FucT-VII andFucT-IV, modify PSGL-1 carbohydrates to generate functional selectinbinding sites, and deficiency in these FucTs, like PSGL1 deficiency,inhibits leukocyte adhesion in experimental models models ofinflammation. To assess the role of these mechanisms, we inducedseizures and epilepsy in PSGL-1, FucT-VII or FucT-IV deficient mice.Continuous video monitoring and direct observations revealed a dramaticreduction in visible convulsions over the 30 days following pilocarpineadministration in PSGL-1, FucT-IV and FucT-VII knockout mice (FIG. 10A,B). The frequency of convulsions over this period fell from 5.2±1.85 perday in the epileptic control group (N=10) to only 2.05±0.78 (P<0.001) inthe PSGL-1^(−/−) mice, and 0.4±0.55 (P<0.0001) in FucT-II^(−/−) mice(FIG. 10A). No spontaneous recurrent convulsions were observed inFucT-VII^(−/−) mice (FIG. 10A, B). The 30 day cumulative number ofspontaneous recurrent convulsions per group was also dramaticallydecreased in PSGL-1^(−/−) (−60.6%), FucT-IV^(−/−) (−92.3%) andFucT-VII^(−/−) (−100%) vs wild-type animals (FIG. 10B). The open fieldexploratory behaviour of PSGL-1^(−/−), FucT-IV^(−/−) and FucT-VIi^(−/−)treated animals was also largely preserved (FIG. 10C, Table 7).

EEG telemetry (FIG. 11) confirmed the behavioral data by showing adrastic reduction in the number of abnormal electrical events and intotal seizure time after SE in mice deficient of PSGL-1 when comparedwith control animals,.and a complete absence of seizures in FucT-VIIdeficient mice was observed by telemetry (Mean number of seizures/mouse:control epileptic group: 44±8.9 (SD, N=10 per group); PSGL-1 deficientgroup: 5.3±2.2, P<0.0001; Average seizure duration/mouse: epileptic:1652 sec; PSGL-1 deficient mice: 4.1±2.4 sec, P<0.001).

Taken together these results show that PSGL-1 and fucosyltransferaseactivity, previously described as a key element for the interactionsmediated by selectins and mucin PSGL-1, are involved in the pathogenesisof seizures and epilepsy.

TABLE 7 Enriched open field test in mice deficient of PSGL-1 and FucTs.Episode Frequency (events/10 min) Mean SEM center Wild type 11.1^(a,b,c) 2.1 PSGL-1^(−/−)  22.3^(a) 2.4 FucT-IV^(−/−)  28.2^(b) 3.5FucT-VII^(−/−)  27.8^(c) 3.1 intermediate Wild type  62.4^(d,e,f) 5.9PSGL-1^(−/−)  96.1^(d,g,h) 3.8 FucT-IV^(−/−) 125.1^(e,g) 3.6FucT-VII^(−/−) 130.9^(f,h) 3.9 borders Wild type  25.9^(i,j,k) 3.4PSGL-1^(−/−)  56.5^(j) 3.1 FucT-IV^(−/−)  89.4^(j) 2.4 FucT-VII^(−/−) 67.4^(k) 1.5 ^(a)p < .001; ^(b)p < .001; ^(c)p < .001; ^(d)p < .001;^(e)p < .001; ^(f)p < .001; ^(g)p < .05; ^(h)p < .05; ^(i)p < .01; ^(j)p< .01; ^(k)p < .01 Cognitive evaluation was based on enriched open-fieldexploration in wildtype versus knockout mice. Post-hoc statisticalvalues (ANOVA) are reported at the bottom of the Table.

The ability of anti-a4 treatment and PSGL-1/FucT deficiency to inhibitnot only the development of recurrent seizures, but also the initialseizure activity is surprising. Pilocarpine-induced vascular adhesionmolecule expression is reduced if seizures are preventedpharmacologically with diazepam, suggesting that electrical activitystimulates the vascular response. On the other hand, prevention ofconvulsant activity by anti-α4 treatment or by PSGL-1 or FucT deficiencyin the current study (and also by interference with ICAM-1 or β2integrins interactions required for leukocyte-vascular interaction inthe CNS) strongly suggests that leukocyte recruitment (at least to theCNS vasculature) may enable or amplify the electrical hyperactivityrequired for seizures. One possibility is that there is a criticalpositive feedback loop between leukocyte recruitment, vascular changesand CNS electrical hyperactivity. In this model, a low level ofconstitutive leukocyte interactions with the vessel wall is required incombination with a suboptimal stimulus to CNS hyperactivity to initiatethe process, with a feedback between inflammatory vascular changes,additional leukocyte-mediated inflammatory changes, and increasing CNSactivity being associated with and required for initiation ofconvulsions. Chronic expression of VCAM-1 after seizures suggests thatleukocyte recruitment may continue, contributing to neuroinflammationand potentially to brain damage that could explain, at least in part,the evolution to chronic epilepsy. Thus, we hypothesize that a cycle ofseizure-induced inflammation and inflammation-mediated corticalstimulation and ultimately damage may amplify initial effects, leadingto SE and to recurrent seizure activity.

We also show that transfused Th1 cells enter into the brain early postseizures. Th1 cells are detected in brain tissue early in thedevelopment of autoimmune diseases of the brain where they areresponsible of the induction of a chronic inflammatory process. The lackof interactions between Th2 cells and brain endothelium suggest that, atleast in early phases of inflammation after seizures, Th1 might bepreferentially recruited. Other leukocyte subpopulations such asmonocytes might have a role in the induction of seizures and/orestablishment of chronic disease, as well, since α4β1-VCAM-1 have beenshown to have a central role for monocyte adhesion to inflamedendothelium in vitro and in vivo. Chronic expression of ICAM-1 andVCAM-1 after seizures suggests that leukocyte recruitment may continue,contributing to neuroinflammation and potentially to brain damage thatcould explain; at least in part, the evolution to chronic epilepsy. Acycle of seizure-induced inflammation and inflammation-mediated corticalstimulation and ultimately damage can amplify the effects, leading to SEand to recurrent seizure activity.

The currently available pharmacological treatments for epilepsy inhibitneuronal excitability but do not address inciting pathogenic mechanisms.Involvement of inflammatory cells in the etiology and pathogenesis ofseizures has been the subject of conjecture, but has not been examinedexperimentally. We show here that multiple mechanisms involved in themultistep process of leukocyte-CNS vascular interactions and recruitmentcan be targeted to alter seizure activity, supporting the hypothesisthat it is blockade of leukocyte recruitment that is responsible for thetherapeutic effect. Our results demonstrate leukocyte recruitment as acomponent of the pathogenesis of epilepsy, and demonstrate thattargeting α4 integrin, beta 2 integrins, VCAM-1, ICAM-1, PSGL-1 andFucosyltransferases prevents and treats epilepsy in mouse models. Ahumanized anti-α4 integrin antibody (Natalizumab/Tysabri) used fortreatment. of multiple sclerosis, a human inflammatory disease of theCNS, is already available for clinical trials. Although adversereactions have been encountered after prolonged Natalizumab treatment,apparently as a result of immunosuppression, this is unlikely to occurwith short periods of anti-leukocyte adhesion therapy after seizureactivity. In addition, a recombinant immunoglobulin chimeric form ofPSGL1, YSPSL (rPSGL-Ig) is currently urider evaluation for theprevention of graft dysfunction in kidney transplantation, and ahumanized anti-LFA-1 integrin antibody (Efalizumab/Raptiva) is currentlyused for psoriasis. Anti-adhesion therapies can also help prevent theoccurrence of epilepsy following brain insults associated withinflammation such as traumatic brain injury, for instance in militarypersonnel in war zones, where seizures and epilepsy present asignificant health problem.

Moreover, our results show that brain endothelium expresses adhesionmolecules either after pilocarpine-induced seizures or kainicacid-induced seizures (FIG. 15). Thus, independently on the experimentalmodel of epilepsy, BBB becomes activated after seizures and expressesadhesion molecules, which can recruit leukocytes from the blood streaminducing BBB increased permeability and neuronal damage.

In conclusion, these results revolutionize understanding of thepathogenesis of epilepsy and seizures, showing a key role for leukocyterecruitment and demonstrating that anti-leukocyte adhesion therapy haspreventive as well as therapeutic effects in this debilitating disease.

Materials and Methods

Reagents. MAbs anti-α4 integrin PS/2, anti-VCAM-1 MK 2.7, anti-ICAM-1 YN1.1.7.4, anti-MAdCAM-1 were from American Type Culture Collection orwere produced in our lab.

Induction of seizures and epilepsy. The study was based on young C57BU6male mice (30-50 days of age, weight range: 19-23 gr) maintained on a 12h light/dark inverted schedule, with access to food and water adlibitum, and habituated to the experimenters for at least two weeksprior to the procedures employed in the present study. The experimentsreceived authorization from the Italian Ministry of Health, and wereconducted following the principles of the NIH Guide for the Use and Careof Laboratory Animals, and the European Community Council (86/609/EEC)directive. Thirty minutes before application of pilocarpine, the animalswere pretreated with methyl-scopolamine (1 mg/kg, i.p.; Sigma, Germany).Subsequently, mice were injected i.p. with 300 mg/kg pilocarpine (Sigma,Germany) diluted in 0.01 M phosphate-buffered saline, pH 7.4 (PBS). Forstatus epilepticus blockade mice were injected with Diazepam i.p. (3mg/Kg) 20 min before pilocarpine administration.

MRI (magnetic resonance imaging) analysis. Evaluation of FeO labeledleukocyte migration. Murine Th1 cells or PMNs freshly isolated from bonemarrow have been seeded in a 24 well plate at 5×10⁶ cells/ml/ well ingrowth medium, and labeled with iron particles (Resovist, Schering AG,solution containing 540 mg ferucarbotran equal to 28 mgFe/ml) at aconcentration of 100 μg/ml. After 14-16 h incubation, cells have beenwashed 3 times in D-PBS; cell viability has been determined by stainingwith Trypanblue, and incorporation of iron particles was evaluated bystaining of cytospins by Mellory (Prussian Blue). PMNs were injected IVinto mice 1h post-SE onset, while Th1 cells were injected 24 h post-SEonset. After 18-24 h mice were perfused with 4% paraformaldehyde andwere observed by MRI using the transmitter-receiver coil configurationdescribed before. Gradient Echo images were acquired using the followingparameters: TR=350 ms; TE=12 ms; matrix size=256×256; FOV=2×2cm2;NEX=12; slice thickness=2; number of slices=10.

Behavioral assessment. Cognitive alterations, evaluated by enrichedenvironment exploration behavior, were recorded by Ethovision 3.0(Noldus Information Technology, Wageningen, the Netherland). Briefly,animals were placed for the first time for 10 min in a square (150×150cm), with three different colored objects in the center. Time spent inproximity of square wall (W), central objects (C) and intermediate zone(I) was used to quantify explorative behavior. Before testing thebehavioural phenotype, studies were carried out in order to evaluate ifthe treatment had any effect on the motor coordination and strength. Theanimals were thus tested for the motor coordination by Rota-Rod (UgoBasile, Varese, Italy), while motor strength was assessed by the GripStrength Meter (Ugo Basile).

Telemetry EEG. Seizures onset, severity and duration were assessed byelectroencephalogram (EEG) acquisition system using telemetrictechnology (Dataquest® A.R.T. Data Acquisition 3.0 for telemetrysystems, Data Sciences International, Arden Hills, Minn., USA). Werecorded 24 h/day for 20 consecutive days, EEG, body temperature andmovements for each single animal.

PMN preparation. Mouse bone marrow PMNs were isolated from femurs andtibias as previously described. Briefly marrow cells were flushed fromthe bones using Hank's balanced salt solution without Ca²⁺ and Mg²⁺.After hypotonic lysis of erythrocytes cells were loaded on top of aPercoll discontinuous density gradient and, after centrifugation cellswere harvested and washed before use.

Production of murine Th1 and Th2 cells. Naïve CD4+ T cells werepositively selected from spleens and lymph nodes of C57BI/6 mice byanti-CD4-coated magnetic microbeads and by anti-CD62-coated magneticmicrobeads (Miltenyi-Biotec GmbH). Obtainment of Th1 and Th2 cells wasperformed as previously described. The phenotype of Th1 and Th2 celllines was determined by intracytoplasmic staining for IFN-γ and IL-4.

In vivo staining of endothelial adhesion molecules. MAbs anti-VCAM-1,anti-ICAM-1, anti-MAdCAM-1, anti-P-selectin, anti-E-selectin andisotype-matched control antibody (anti-human Ras) with Alexa Fluor 488(Molecular probes) and injected intravenously. Cerebral vessels werevisualized using the intravital microscopy setting as previouslydescribed.

Patients. All human samples were obtained from the Department ofMedicine and Public Health of the Insubria University, Varese, Italy(O.A.). 10 long-term epileptics with no concurrent inflammatory braindiagnoses, 10 age-matched controls, and 10 patients with noninflammatory neurological diseases (almost all diagnosed with Parkinsondisease) were included in the study. All patients considered in thisstudy died of non-inflammatory brain diseases.

Statistics: Statistical analysis of the results, was performed by usingPrism software. A two-tailed Student's t test was employed forstatistical comparison of two samples. Multiple comparisons wereperformed employing Kruskall-Wallis test with the Bonferroni correctionof P or by using ANOVA. Velocity histograms were compared usingMan-Whitney U-test and Kolmogorov-Smirnov test. Differences wereregarded significant with a value of P<0.05.

Immunofluorescence. Free floating sections were washed in PBS at roomtemperature and permeabilized for 1 hour in PBS containing 0.3% TritonX-100, 1% bovine serum albumin and 2% normal goat serum, the samesolution was used to dilute the antibodies. Subsequently, sections wereincubated overnight with rat anti-mouse CD 3 (1:400, Serotec, Oxford,UK) or rat anti-mouse Gr-1 (1:400, Serotec, Oxford, UK). After washes,sections were then incubated in fluorescein (FITC) conjugated affinitypurified goat anti-rat IgG (1:100; Jackson Laboratories, INC; Baltimore,Pa.) or goat anti-rabbit IgG (1:200; Jackson Laboratories) for two hoursat room temperature. Finally, sections were collected on plysine-coatedslides, mounted with with Fluorescent Mounting Medium (DAKO, Milan,Italy) and observed with a Zeiss LSM 510 confocal microscope. All imagesfor publication were composed in Adobe Photoshop software (version 7.0;Adobe Systems, Mountain View, Calif.). Sections treated as above, but inthe absence of the primary or secondary antibody were used as control.

Immunohistochemistry. Paraffin sections of human brains (see Table 1)were processed for immunohistochemistry using the Labeled Polymermethod. Briefly, deparaffinized sections were rehydrated and endogenousperoxidase activity was quenched by 15-min incubation in a solution of3% hydrogen peroxide in methanol. After washing in 0.05 M Tris-HClbuffer (pH 7.6) sections were incubated for 30 min at room temperaturewith the following primary antibodies: anti-human CD45, Leucocyte CommonAntigen (1:100, Dako), anti-human CD3 (1:100, Novocastra LaboratoriesLtd. UK), anti-human Myeloperoxidase (1:500, Dako). Immunoreaction wasrevealed by incubating sections with immunoglobulins conjugated toperoxidase labelled-dextran polymer (Envision+™, Dako, Milan, Italy) for30 min at room temperature. Finally, all sections were reacted with 0.05M 3,3-diaminobenzidine tetrahydrochloride for 3-5 min and counterstainedwith hematoxylin. Sections were then dehydrated, mounted and observed ina Olympus BX51 photomicroscope equipped with a KY-F58 CCD camera (JVC).

Intravital microscopy. C56BI/6 young males were purchased fromHarlan-Nossan (Udine,. Italy) and were housed and used according tocurrent European community rules for the usage of laboratory animals. At6 h or 24 h post seizure induction with pilocarpine, mice wereanesthetized by intraperitoneal injection (10 ml/kg) of physiologicsaline containing with ketamine (5 mg/ml) and xylazine (1 mg/ml). Therecipient was maintained at 37° C. by a stage mounted strip heaterLinkam CO102 (Olympus). A heparinized PE-10 polyethylene catheter wasinserted into the right common carotid artery toward the brain. In orderto exclude from the analysis the non cerebral vessels, the rightexternal carotid artery and pterygopalatine artery, a branch from theinternal carotid, were ligated. The scalp was reflected and the skullwas bathed with sterile saline, and a 24mm×24mm coverslip was appliedand fixed with silicon grease. A round chamber with 11 mm internaldiameter was attached on the cover slip and filled with water.

The preparation was placed on an Olympus BX50WI microscope and a waterimmersion objective with long focal distance (Olympus Achroplan, focaldistance 3.3 mm, NA 0.5∞) was used. Blood vessels were visualized byusing fluorescent dextrans: 3mg of FITC-dextran (148 kD; Sigma) and/or 6mg of TRITC-dextran (155 kD; Sigma) were diluted in 0.3 ml sterilephysiologic saline and centrifuged for 5 min at 14,000 g (each mousereceived 0.05 ml supernatant). 2.5×10⁶ fluorescent labeledcells/condition were slowly injected into the carotid artery by adigital pump at a flow rate of 0.13-1 μl/s. Leukocytes were labeled witheither green CMFDA (5-chloromethylfluorescein diacetate) (Molecularprobes) or orange CMTMR (5-(and-6)-(((chloromethyl)benzoyl)amino)tetramethylrhodamine) (MolecularProbes). The images were visualized by using a silicon-intensifiedtarget videocamera (VE-1000 SIT, Dage MTI, Michigan, Ill.) and a SonySSM-125CE monitor. Recordings were digitalized and stored on videotapesemploying a digital VCR (Panasonic NV-DV10000). The recordings were madeduring the injection of the cells and for a few minutes after theinjection was ended.

Video analysis was performed by playback of digital videotapes in realtime or at reduced speed, and frame by frame. Vessel diameter (D),hemodynamic parameters and the velocities of rolling were determined byusing the NIH Image 1.62 software. The velocities of ≧20 consecutivefreely flowing cells/venule were calculated, and from the velocity ofthe fastest cell in each venule (V_(fast)), we calculated the mean bloodflow velocities (V_(m)): V_(m)=V_(fast)/(2−ε²) where ε is the ratio ofthe lymphocyte diameter to vessel diameter. The wall shear rate (γ) wascalculated from γ=8×V_(m)/D (s⁻¹), and the shear stress (τ) acting onrolling cells was approximated by γ×0.025 (dyn/cm₂), assuming a bloodviscosity of 0.025 Poise. Lymphocytes were considered as rolling if theytraveled at velocities below V_(crit) (V_(crit)=V_(m)×ε×(2−ε)).Lymphocytes that remained stationary on venular wall for ≧30 s wereconsidered adherent. At least 150 consecutive cells/venule wereexamined. Rolling and arrest fractions were determined as the percentageof cells that rolled or firmly arrested within a given venule in thetotal number of cells that enter that venule during the same period.

Determination of BBB permeability. MRI experiments were performed usinga Bruker Biospec Tomograph equipped with an Oxford, 33-cm-bore. Animalswere anaesthetized and placed in prone position into a 7.2 cmtransmitter birdcage coil. The signal was acquired by a 1.5 cm activelydecoupled surface coil. The tail vein was cannulated for injection ofcontrast agent (Magnevist, Schering 100 micromol/kg). Multislice,T1-weighted Spin Echo images were acquired before and up to 24 min afterinjection of Magnevist. The acquisition parameters were: TR=350 ms;TE=14.4 ms; matrix size=128×128; FOV=3×3 cm2. Twelve contiguous, 1mm-thick slices were acquired to cover the whole-brain.

In vitro adhesion assays. Adhesion was performed on purified integrinligands as reported29. Blood leukocytes were isolated after hypotoniclysis of erythrocytes. Adhesion assays were performed on eighteen wellglass slides coated with VCAM-1. Cells were treated with pilocarpine atdifferent concentrations and time points. After 20 min, slides werewashed, fixed and computer-assisted enumeration of bound cells wasperformed as described.

All publications and patent applications cited in this specification areherein incorporated by reference as if each individual publication orpatent application were specifically and individually indicated to beincorporated by reference. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present invention is not entitled to antedate suchpublication by virtue of prior invention.

It is to be understood that this invention is not limited to theparticular methodology, protocols, cell lines, animal species or genera,and reagents described, as such may vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to limit the scope ofthe present invention, which will be limited only by the appendedclaims.

As used herein the singular forms “a”, “and”, and “the” include pluralreferents unless the context clearly dictates otherwise. All technicaland scientific terms used herein have the same meaning as commonlyunderstood to one of ordinary skill in the art to which this inventionbelongs unless clearly indicated otherwise.

1. A method of preventing seizures in an individual mammal that hasepilepsy, said method comprising: administering to said individualmammal an effective amount of an antibody specific for an α4 integrin toinhibit the recurrence of seizures.